Hyundai - Elantra :: 2002 - Rough Idle And Misfire When Hot / Intermittent Hesitation When Accelerating

2002 Hyundai Elantra GT 2.0L 140k miles

Symptoms:

- Intermittent rough idle when hot, slight shutter, surges between 700-800rmp
- Intermittent hesitation when accelerating, cylinder 2 misfire when hot and under load
- Misfires in all gears under load, mostly when under 2000rpm
- Code P0302 when scanned, no other codes
- Symptoms appeared suddenly, not gradually over time

What's been changed:

- Replaced spark plugs, little or no improvement. Old plugs looked worn, but generally in good shape with no significant deposits.
- Cleared code and swapped injectors between cylinders 1 and 2, after test drive P0302 code came back, so it seems that the injectors are good. If the injector were bad I would have expected the misfire to change from cylinder 2 to cylinder 1.

Inspection and Testing:

- Ignition System Testing
- Spark plug wires and primary coil are within specification.
- Secondary coil resistance is high on both packs. Could this be causing a problem with just cylinder 2? Is it worth replacing?

Spark Plug Wires: Specification: 5.6 Kohm/meter +- 20%Cylinder 1: 2.49 Kohm (Longest)Cylinder 2: 2.03 KohmCylinder 3: 1.64 KohmCylinder 4:1.36 Kohm (Shortest)
Primary Coil: Specification : 0.58ohms +- 10%Actual: .6 and .6
Secondary Coil: Specification: 12.2 Kohms +- 15%
Actual (Cold): 16.03K for Cylinder 2-3 pack and 15.94K for Cylinder 1-4 pack
Actual (Hot): 18.54K for Cylinder 2-3 pack and 18.44K for Cylinder 1-4 pack

Air/Fuel System Testing:Fuel system seems to check out. I do not believe the problem is fuel related. There are no obvious cracks or leaks on the intake manifold. A good spray of Carb cleaner all around the manifold causes no change in idle. I might try propane later. No obvious vacuum leaks.

Fuel Injector: Specification: 13.1-14.5 ohms
Actual: Cyl 1: 14.9, Cyl 2: 15.3, Cyl 3: 15.3, Cyl 4: 15.7

Compression Testing:Compression is not great, but within specification. Could the slightly lower compression in Cylinders 2 and 3 indicate a head gasket leak between those cylinders? Could this cause a misfire in Cylinder 2?

Dry Compression: Specification: 145-218psi, <15psi between cylinders
Actual: Cyl 1: 165, Cyl 2: 155, Cyl 3: 155, Cyl 4: 160

Oil/Coolant/Tailpipe:

- Oil looks normal, not brown or milky
- Coolant looks normal and is full, no signs of leaking (coolant has not been changed in a very long time, could a coolant flush work?)
- Exhaust looks and smells normal from tailpipe.

Sticking valve? How would I check this? Bad sensor somewhere? Doesn't a bad sensor usually throw a code?

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Ford Super Duty (1999-2016) :: 2002 F250 V10 Rough Idle / Misfire Under Load

I have a 2002 F250 CCSB Lariat 4x4 with the Triton V10, I'm up to 232,000 miles so far and fairly happy with the old girl. Just this weekend, I noticed some hesitation when at idle and even more rough running when under slight load. The misfire/hesitation is worst when going up a slight hill, when the truck is accelerating at low RPMs.

I am getting zero trouble codes or freeze frame conditions on my scanner. What should be my order of diagnosis? Vacuum test at line from PCV to TB, COP test? EGR inspection? Plug inspection? Also, how do you test a coil if resistance is not a reliable method?

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Camry :: 2002 - Intermittent Misfire Code P0300 / 301 And 302

I've got the intermittent misfire codes on my '02 Camry, and after changing the spark plugs and the ignition coils the problem still persists.

At first there was no noticeable misfire, I took it to two different mechanics and neither said they could find anything wrong. A few weeks later the misfire became noticeable when I'm sitting at a stop light. I can feel an occasional rumble in the engine.

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Camry :: 2003 4cyl / Auto - Hesitation Under Load

Our Camry has about 105,000 miles on it. Car is well maintained, I change the oil every 3 k or so and the air filter is clean (although it is not a factory air cleaner- it is a K&N filter). Other maint is done as specified by the warranty/maintenance book although the car is long out of factory warranty.

We occasionally pull a 800 lb pop-up tent trailer and just got back from the Sierras after driving up some pretty tall passes with it. Car ran great, got great mileage, temp gauge rock steady. I say this because it is probably the most stressful driving we do with this car. While we live in the city we are retired and the car is not exposed to constant heavy traffic, dust or snow. Mileage seems to have remained pretty steady, even with the hesitation.

Got home from the mountains and a couple days later the car began to hesitate when under load. The hesitation shows up as a slightly uneven surge when the car is going up a hill or when it is cold. About 20 mph the car seems to momentarily stop accelerating, then evens out and upwards of 40 mph I don't feel it at all. The hesitation is getting a bit worse over the last couple days in frequency, but still isn't felt on the freeway. I don't know if the hesitation is related to the recent trip to the Sierras.

I hooked up my OBD II computer to see if there are any DTCs, none shown, even left the computer on the car for a day to see if anything might pop up when the car surged, but the computer isn't seeing trouble codes.

My other thought was "got some bad gas", ran the tank out and put in new gas, fuel injector cleaner and dryer. With one new tank it hasn't worked. I haven't replaced the fuel filter yet.

Tried driving the car in 1st and 2nd gear only and found that the hesitation isn't dependent on what gear I'm in, but seems to be more about the speed and load. In neutral, slowly revving the engine, I don't detect anything that sounds or looks like a hesitation (just watching the tach).

Been reading about problems some Toyotas have had with unintended acceleration but I'm not sure that is my problem. I have to admit I didn't know that my Camry was "drive by wire" and maybe I don't understand it enough. Maybe a "reflash" might be needed?

My sense is that I should go ahead and do the next major maintenance items including plugs, but if I had a bad plug or plug coil wouldn't that show up as a Diagnostic Trouble Code item?

Could this be a bad injector or fuel filter? Wouldn't they produce a DTC? How do I break down the next steps?

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Camry :: 2003 - Power Loss And Hesitation Jumps Under Load

My 2003 Camry loses power and starts to hesitate or miss-like under load, but when cruising along not under load it runs smooth. There is no check engine light coming on.

I have changed the fuel pump and fuel filter in the tank.
I have changed the spark plugs.
I have added injector cleaner and fuel treatment to the fuel.
I have cleaned the air filter and air filter compartment.

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I have a 98 k1500 5.7 vortec. I was driving and the next thing I knew my truck lost power and would misfire at an idle but only when under a load (in drive with foot on brake). The last time something like this happened an injector came out of place. So that's where I started. I wound up changing the whole spider injectors and ALL the gaskets, upper and lower. I put everything back together and the problem was still there so basically I am back to square one.

I then pulled spark plug wires while running to see if I could isolate the misfire and found that I could pull all 4 wires on the passenger side without any difference in while it was running. So basically my truck is currently running on 4 cylinders and they all happen to be on the driver side. I checked my compression on the passenger side and all 4 cylinders have 180 psi so that rules out the head gasket being blown. I am getting 4 codes , 520, p1345, p0155 and p0161. I know that i have to get tge truck properly timed with a computer but i don't think that would cause my problem.

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Ford F-150 (2004-2008) :: Misfire / Rough Idle Under A Bit Of Load (acceleration) And Uphill

2005 Ford F150 lariat 5.4

I had a misfire under a bit of a load (acceleration) and up hills. I changed spark plus with OEM Motor craft ones, truck ran super nice for a couple week.

Had the engine light flash, slow down and the RPM go up a tiny bit then back down and the light goes off

Now I'm back to miss fire different location, and a rough idle. I've swapped coil packs around and the miss fire stayed on cylinder 4.

Spark plug screwed or injector or ?????

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Ford - Explorer :: 2003 - Misfire On Cylinder 8 / Running Rough At Idle And Under Load

126000kms on 03 explorer 4.6 truck started. Running rough at idle and under load.... Code came up for cyl 8 injector. Replaced injector... problem still there. Switched cop and plug with another cyl and plug.... same code and cycl 8 is definitely not working. Would a generic problem always affect i cylinder. I even checked wire clip on for injector... it appears ok. There is power to injector wire clip.

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Lexus SC430 :: 2002 - Intermittent Hesitation Or Stumble / Momentary Power Loss

When I take off from a start it will intermittently stumble or hesitate, seems to be around 1500 rpm. have also noted it at higher speed while cruising. its more like a momentary power cut than a miss fire.

So far I have done the following

new fuel filters
clean MAF
new PCV valve
new spark plugs
check all hoses and plugs etc
injector clean
checked techstream for codes. there is one for a heated O2 sensor but dont think thats it.

2002. SC430

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Chevrolet - Aveo :: Intermittent Misfire At Idle And Between 50 And 55 Mph When Going Up Incline

My 2004 Chev Aveo has recently developed a strange misfire pattern. I am hoping to get some clues before I take it to a mechanic. It only misfires when at an idle and then again between 50 and 55 mph going up an incline. Above 55, it runs fine. Between 5 and 50, it runs fine. It has 109,000 miles and had the timing belt changed at 90,000. What would be causing this?

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Ford F-150 - 1997-2003 :: 1998 4.6L - Intermittent Misfire When Accelerate And At Idle

So my truck started to intermittently misfire about a month ago . I changed the spark plugs wires at first and it seemed to get better but it still had a misfire . I replaced the spark plugs and ignition coils and the misfire is still there . Up until the other day it was a noticeable issue but still drivable with . On my way home from work it got alot worse and started to misfire any time I tried to accelerate and now is noticeable at idle now as well.

I checked the fuel injectors resistance and they are about 14.8 ohms . I am not getting any codes for a misfire . I tried to pull the fuel injector connectors to try to find the source of the misfire but could noticeable change in engine rpm. Where to go from here and what I should check first? Would a clogged fuel filter cause something like this ?

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Ford Ranger / B-Series :: 2006 3.0L - Intermittent Low Compression And Misfire At Idle

I bought a used Ranger a couple months ago and it ran fine when I test drove it but a week later it started having a misfire every now and then at idle.. I must have gotten pretty unlucky with the test drives..

The misfire comes and goes, it will run fine for a week or two and then it will misfire at idle for a week or two. It only seems to misfire at idle, the truck runs rough/shakes but once you give it a little gas and start moving it goes away. Usually it has a check engine light on from startup when it's misfiring and it goes away on days that it's running fine; it will occasionally misfire at idle with no check engine light. Sometimes when its running really rough the CEL flashes while it's misfiring at idle and I've actually restarted it real quick and the misfire went away for a bit. The engine codes that come up are misfire on startup and misfire on cylinder 4.

I've tried cleaning the MAF sensor, replacing the fuel filter, testing for spark and compression. Compression was 150-155 PSI on all cylinders, however, the compression on cylinder 4 is different depending on whether the truck is running well or not. When it's misfiring the compression on cyl. 4 is 90 PSI and when it's running fine it's 150 PSI. I'm not sure what could be causing intermittent low compression like that?

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Ford Escape / Hybrid :: 2004 - Intermittent Rough / Low Idle / Misfire On Startup

My g/f's 2004 Ford Escape (3.0L V6 AWD 112,000mi) is acting up. After a full day of sitting, with the second half of it raining steadily, she was driving her Escape and it was acting funny (miss-firing, she said). The engine light came on and soon began blinking. She got to my house shortly after it started this. We left it and I drove for the day. Later that night, I drove it and it seemed fine. The engine light was on, but not flashing anymore.

The next day I took it my friend that was a Saturn mechanic and now working at a KIA dealership (same owner as the former Saturn and current Buick/GMC and Chevy Dealer). It ran fine for me. So he tries to scan it, his Mac Tools scanner won't read it. The KIA scanner wouldn't read it. I drove it the Ford dealer up the road. They said they couldn't get to it until after lunch, I just want the codes read. They re-iterated, and I told them to pound salt and went to an independent shop where I know a guy. They read it right away for me. "Mis-fire on start-up" & "Cylinder 4 Mis-fire." were the two codes stored. He cleared them.

She got the tune up basics (plugs, wires, air filter, etc) and did the complete tune-up herself yesterday. (I was impressed). She put 94 in the tank and some fuel system cleaner in it as well. She said there's been no change and today I finally saw what it was doing. Sometimes during idling at a stop light, the RPMs will drop to almost zero, the lights dim but so far it has not stalled. It'll do this for several seconds, then correct itself and idle normally.

Currently, the engine light has not come back on. She's thinking coil pack (each cylinder has a coil on these engines) on #4. She wants to switch it out with #1 and see if the problem follows. I think that might uncover the cause, or it could be the battery. It's the original, never been replaced and has a lot of miles on it, but it survived this past winter, without trouble. In my experience, most batteries crap out due to age in the fall when the cold snaps start.

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Passat (B5) :: 2002 V6 - No Heat / Cold Air Blowing At Idle And Under Load

2002 Passat v6 - climatronic control...

I have just cold air blowing at idle and under load. I have read posts and checked the following: temp remains at 190, heater coil hoses-both are hot and removed the dash to see if the flapper door (red arm) was moving-it is. Any other things I can check?

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Caravan/Voyager :: 2002 - Check Engine Light On / Intermittent Misfire

I have an 02 Dodge Caravan 3.3 L Flex . It had initially stalled and wouldn't start. Check engine light was on. Had it towed to a Cert Mech. He said it needed a "Major" tune-up. I let him do this. It included: New Coilpak, plugs, plug wires, cam-sensor, crank sensor. That's what was on 1st invoice.

It started, but was still running very rough. He then recommend a new PCM. After choking on his estimate, and paying the initial invoice, I decided to let someone else have at it. Mech # 2 installed a "Rebuilt" PCM, New Battery, and a PCV Valve.

It runs good now BUT, ...It has this weird idle Misfire. The only time it happens is at a stop light when at idle. And it doesnt do it all the time. This check engine light is not on... At this point, all I want to do is sell it.I have over 1K in repair costs and still can't get rid of this misfire.

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Subaru - Forester :: 2002 - Revs In Idle / Hesitation On Accelerating

My subaru forester, 2002, with low mileage (40K) had routine maintenance 2 mos ago. Now sounds like it revs when in idle, and today began hesitating when I accelerate (a few seconds or so). I plan to take it in but wonder if there's insight before I go in cold (I know nothing about cars). Read on forums could be 02 sensor.

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A problem just popped up yesterday. 09 Camry, 2.4L, SE, about 178k on the odo. Started out as a slight hesitation when trying to accelerate from a stop, hardly noticeable, in the am. As day progressed it got much worse (very little driving but about 3 to 4 trips). By night the car wants to die upon first start up. Engine will rev higher, then drop, then rev, and will drop way low and stutter and die if I don't feather gas. Very bad hesitation today when trying to get moving. This morning it was revving high, low, high, low (high meaning a little over 1000), then dropped, stuttered and died. Cranked again fine.

My in gear idle rpm is about 650. I will be checking the plugs and throttle body later today as several months back I had issues that seemed to be related to those. I have my suspicions, but want to get opinions. I filled up the tank yesterday morning. Was about 14 degrees yesterday morning, warmed up to around 30. In the 40s today. Engine does get to normal temp, all that fun jazz. I am thinking shitty gas....?

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My 2002 V4 Camry has developed a consistent hesitation. It only occurs during the first 15 minutes (or so) after cold startup. I've replaced: plugs, 2 O2 sensors, Mass Air flow, and EVAP Canister.

Am about to try the throttle position sensor.

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