Accent MC (2006-11) :: 2009 - Code P0300 / CEL Came On And Stayed Over Multiple Startups
Had the CEL come on twice in the last few days. The first time, a restart of the car took it away. The second time, it came on and stayed over multiple start ups.
With Torque Pro and a bluetooth OBDII dongle I read: P0300 - Powertrain, Random/Multiple Cylinder Misfire Detected
From the Internet:
Possible causes
- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure
I wish it wasn't so broad... But, as the car is about to hit 60,000 miles, I plan to replace the spark plugs (NGK), engine air filter, cabin air filter. Just had the timing belt done last week. I will check all of the intake couplings for tightness.
For others who use Torque, what other settings could be useful in pinning down this issue for me? I cleared the CEL this morning; it didn't come back yet.
Accent MC (2006-11) :: 2007 GLS - Random / Multiple Misfire And Code P0300
I have a 2007 Hyundai Accent GLS. I just got it from a used car dealership (local) and it runs perfectly. It had a misfire code when i first got it, for all cylinders plus the p0300. It went away when i started the engine again, and didnt come back til a month later (Now). now it wont go away.
I went to advance auto and had them use their OBD2 reader for a trouble code and i got p0300, p0301, p0303, p0304. No other codes present.
I am not feeling anything bad, and from what I am told, a misfire feels like a hard shift. This is of course after getting the plugs and wires changes as well as an oil change. Standard preventative maintenance.
The mechanic used OEM parts got from local parts shop. i think the OEM plugs are the copper ones. I would have preferred iridium as they arent that much more expensive but I don't want to pay for another plug change.
The only symptoms I can think of, is that according to google, I should get around 380 miles to a full tank (11.9 capacity, 32 mpg city). I am only getting 280 from full tank to gas light.
I have also gone through a lot of oil. I checked the dipstick and it was below the low line, so i bought a quart of high mileage oil (same exact brand and type of oil that i gave to the mechanic to use) and it went to just above the full line. This was at around 1500 miles after oil change.
After visiting multiple sites about misfires, i found a few things that caught my attention. One is a site called auto service professional, which talks about the OCV for the MC accent. A lot of sites also recommend gaping the plugs at .035.
Impala - Chevrolet :: 2000 3.8L V6 - Code P0300 Multiple Random Misfire
I have a 2000 Impala with a 3800 V6 series 2 with 165,000 miles. The only code I had was a P0300 Multiple random misfire that occured off and on at first, Worse in the city Better on Highway. It would start running on half the cylinders and bogged down, with the check engine light flashing, after getting onto the highway it would straighten itself out at first. I thought i had water in the gas so i ran some heat through it. straightened out for a day then happened again so I thought maybe a should run some premium gas in it, The car ran like total crap until the premium was gone, so i thought maybe it's running too rich, I put 87octane in it and it ran great for a day or two, then it gradually got worse to where it would not straighten up on the highway, tried to die at stoplights and i had to drive it with 2 feet to get it home and park it. I've replaced the battery, spark plugs, wires, ICM checked good, coil packs are good, replaced fuel Pressure regulator, looked for arcing on the spark plug heat shields and it will not start. It turns over but doesn't try to ignite and when I get the slightest rumble of ignition, it backfires up through the manifold and I see a puff of gas or light smoke by the exhaust manifold.
The car had a vacuum leak around the intake manifold cover gasket and a leak on the fuel rail. I pulled the fuel rail off my impala, snugged up the rest of the intake bolts then disassembled the fuel rail, flushed it out and cleaned the injectors the best i could, then reassembled it. before i re-installed the fuel rail I hooked it up to the fuel lines outside of the engine and tried to start the vehicle. all injectors had a nice spray pattern. So i installed the rail and it still didn't start but it had more combustion than before although it's still backfiring like before. Checked the fuel pressure by turning the key on and the fuel pressure went to zero very fast. I blew the rail out with air so to make sure i didn't damage the regulator I replaced it with the old one, ran the test again with same results, so i reinstalled the new regulator. I performed the fuel pressure test a few more times while moving the fuel hoses and when i moved the back supply line the vacuum loss stopped then dropped to zero when i let off of it. So I replaced the fuel line connector and O-rings on the injectors. It no longer has a vacuum leak.
I cleaned the EGR Valve out and had no luck there, then I removed the Idle Air Control Valve-pushed the pintle in, re-ionstalled it and WooHoo! it started! Although it still ran like crap with the same random misfire I was still happy to hear it start.I pulled the plugs on it to do a compression test and all 6 cylinders have between 180-190psi so the engine is in good condition mechanically. I installed new plugs before getting the car restarted and when i removed them for the test they were covered in thick black soot after running for roughly 15 minutes max.
I have (2) 2000 Chevy Impala's so I've swapped sensors from my wifes car to see if it would fix it. I've tested the following MAP, MAF, IAC, coil packs and ECM. None of these made the car change. I believe it is a timing chain because the car has never had a new timing chain and is way overdue, but I haven't had a code for a crankshaft position sensor. Can the timing chain be bad without throwing a code? It's not out of time enough to change the valve timing because I had a good compression test but its not firing right and still has the multiple random misfire. I have not checked or received a trouble code for o2 sensors, crankshaft position sensor or cam sensor. Something has the timing retarded and is dumping extra fuel into the engine because my new plugs looked like they were in the engine for a year.
Chevrolet - Avalanche :: 2003 - P0300 Code / Multiple Or Random Misfire?
My 03 Chev Avalanche is giving me a P0300 code (multiple or random misfire). With no distributor or individual coil is this something I can fix myself or is it shop time?
View 6 RepliesSonata NF (2006-10) :: Random Misfire Code P0300 - Check Engine Light Flashing
I know it is a random cylinder misfire code however I started my car in the morning and it was fine I moved it and put it back in my driveway. I started it up later and waited for it to heat up i came back outside 10 min later and my check engine light was flashing and my car was shaking like crazy you could tell the engine was misfiring like crazy. I had under a quarter of a tank but not empty yet. I shut it off and turned it back on and it was still doing it. I drove the mile to the gas station the way it was.
Under partial throttle it was revving to 4500 and over 5, had to let of throttle to make the car shift up a gear. I filled up and started the car again performed fine after that however the check engine light was solid now and still on. I went to my local mechanic and he read that code P0300. I changed my spark plugs that day and they were crap the original spark plugs I have 65,xxx on my car now. Car is smooth now. I cleared check engine when i saw him first and it did not come back on all day even before i changed the spark plugs later that night. Why my light was flashing and why my car was acting like that till i filled up?
Passat (B5) :: 2001 / 1.8T - Multiple Misfires On All Cylinders / Lean Air Code
I have a 2001 1.8T Passat. I bought it used recently and have had tons of problems. I have been getting a lean air code for some time now and I think I recently resolved that. I had to replace a few vacuum lines, MAF, exhaust flex pipe (it was broken), fuel filter and fuel pressure regulator. The car was still running bad and throwing a lean air code (Bank 1) so I finally changed the O2 sensor and I think that did the trick. Now every time I start the car I get misfires until is warms up. I get misfires on all cylinders along with the multiple misfire code.
View 5 RepliesElantra XD (2001-06) :: Multiple Misfires Due To A Failed Coil - Code P0422
A few months ago I had multiple misfires due to a failed coil. When it happened I drove it enough to get to an Advance auto to have the code checked that came up. After I replaced the coil the car ran fine, but then the engine light came on with the P0422 bank 1 code. Does this mean the manifold cat converter is shot? The car runs fine except for what feels like the transmission trying to decide where it wants to be around 40mph (like it's shifting back and forth, don't know if it's related). I have a flex pipe that is leaking and needs replaced. I haven't noticed any loss in MPGs (consistently 26mpg city since I started checking). I have 133k miles.
View 8 RepliesSonata NF (2006-10) :: Error Codes P0300 And P0276 On LX V6
I recently got a problem with my 2006 LX V6 with 65k mils on it. The car had a few times a rough Idle so I hooked up my OBDII scammer ant got two failure codes:
P0300 miss fire
P0276 problem with Injector #6
Which one is the cylinder #6. I took of the engine cover and checked the connectors to the valves in the front row. I assume cylinder number 6 is in the back row and hard to get access.
Golf IV / Jetta IV :: OBDII P0300 - Random Misfires Right On Startup
2000 Jetta MKIV ... 2.0L GL
I've been dealing with random misfire codes on my Jetta (P0300, P0301-P0304). I've since replaced the spark plugs, wires, fuel filter, MAF senor, & camshaft positioning sensor but the problem still persists. The misfires occur right on start-up and don't stop which is leading me to the coil pack being bad.
Phaeton :: 2006 - P0300 Code On W12 / Intermittent Misfire
I took my 2006 W12 to get its yearly smog check, and it will not run "air" monitors due to intermittent misfire. The code is P0300.
Any way clearing this up? (I could find no air leaks)....
Corolla / Matrix 2009-13 :: Check Engine Light Code P0300 / P0302 And P0304
Check engine light came on. Codes are P0300, P0302, P0304. Plugs were previously changed. Plugs look good. Changed both coils. Light still one. Injectors also previously cleaned. What else should we check for? Valves hanging? Anything else to check for?
View 5 RepliesPrius (Gen 2) :: 2005 CEL On And Multiple Misfires
2005 prius. the car is pulling three codes misfire cyl1, misfire cyl2, and multiple misfires. The car has over 450000 miles on it and runs like a dream. I just replaced they spark plugs and the coil packs in each cylinder. The cel codes are still there after clearing them. I am willing to replace the fuel injectors but just seems weird that two of them would go out like that together.
View 4 RepliesPassat (B5) :: 2002 2.8 V6 - Random Multiple Misfires?
I know the ignition coil are a big thing but I'm going to be buying this car this week and so I need to see how much less to offer the guy because of this issue. Is there anything other then the ignition coil that it could be? What's worst case scenario? And also would it be ok to drive it home about 60 or so miles with this going on? I'm guessing it's doing the misfires at idle.
View 6 RepliesGolf IV / Jetta IV :: 2.0 AVH - CEL Flashing And Random Multiple Misfires
It all started a few months ago.... I started my car, and it started noticeably misfiring, CEL flashing and everything. I scanned it with my vagcom and it came up Cylinder 1 Misfire and Random Multiple misfire. I popped the hood, made sure everything was seated correctly, and shrugged.
Ordered some new wires for it, since it had 80k miles on it with original wires, I figured why not. The misfire didn't come back.
A few weeks later, same thing happened. Misfires, flashing CEL, same codes. I ended up driving it the 5 minutes to work anyways and figured I'd look at it later after I got off.
8 hours later I started it up again, ran like a champ, no CEL on. The problem didn't come up again for 3-4 weeks.
So now, without fail, every month or so, I'll get the same issue. It doesn't matter if it's raining or sunny or cold or warm. But if I let it sit for a few hours, it'll act like it never happened.
Now, I haven't replaced the coil pack yet, simply because it doesn't sound like a coil problem, but I might do it just for the hell of it. New plugs and wires have already been done.
Passat (B6) :: Shakes At Idle - Multiple Random Misfires
So I took a trip from Dallas to Florida, and on the way back my check engine light came on. The car shakes at idle, almost like it wants to take off. I drove it back to Dallas like that since the car runs normal on the high way. I got it scanned at autozone and the code said it had multiple random misfires. I'll be taking to the dealer in the morning, but what it could be? The car jumped over 50K during the trip hopefully the dealer will be nice and cover it.
View 4 RepliesAccent LC (2000-05) :: Getting Codes For Multiple Misfires On Cylinder 1 / 2 And 4
I have a 2000 lc 1.5l ... I just rebuilt the motor machine shop work and all it Will start and run for 3 seconds and then die. If I hold the gas pedal it will run but sound rough and as soon as you let go it dies I have been able to get codes multiple misfires, misfire cylinder 1, misfire cylinder 2, and misfire cylinder 4 I have put brand new plugs (copper core ngk), wires coils, crank sensor, cam sensor, iac, tps, maf and the injectors all have new orings it also has ntk o2 sensors that might have 1000 miles on them...
View 1 RepliesPontiac - Grandam :: 1997 GT 2.4L Quad 4 - Multiple Misfires
I have a 97 Pontiac Grand Am GT 2.4L Quad 4, my problem is that it misfires and the engine runs rough. You can smell fuel, but there is no fuel leak. I have about 155k miles on the car, never had no serious issues with the car, the car has been great, I’ve owned it since early 2000. Little history on the parts I’ve replaced this year is the following spark plugs x3, spark plug boots x2, timing chain, Timing chain tensioner, camshaft positioning sensor, throttle positioning sensor, fuel pump, fuel filter, air-intake manifold gasket, throttle body gasket, IAC, ignition coils, ignition coil housing, ignition coil wiring harness, swapped the Ignition control module, checked the fuel injectors for solenoid clicking, replaced water pump, thermostat, swapped EGR’s.
Maybe some other parts I can’t remember but I have done a lot trying to figure this out. Also took it to a garage and told them what I have done and the first place they looked was the fuel pump and said it tested at 20psi and called for 40-60psi so they replaced it and problem was still there. They had it for a week and half and couldn’t figure this problem out. Thinking about replacing the ignition coil housing again just to see maybe bought a bad one. Also done the three checks for head gasket blown, milky white oil, anti-freeze bubbling from the reservoir and compression check, all checked out fine. Ran gunk fuel injector cleaner through it several times.
Deville :: 2000 - Codes Keep Showing Is Po300 Multiple Misfires?
My old pump wasnt building pressure so i put a new filter on and i switched wit a used one from an old car i had.key on engine off Pressure goes to 45 then instantly starts droppin? Once i turn key an do again same thing... Car is starting tho. fuel Pressure around 38 while idling. I pulled fuel rail up and looked for leakin injectors.. There was none yet pressure still bled down kinda quick. I also have my cat aloose to keep from messing it up any further. Only codes keep showing is po300 multiple misfires.
View 2 RepliesPassat (B5) :: 2002 - Getting Multiple CEL For Catalytic Converters And Cylinder Misfires
Getting multiple CEL's for the catalytic converters and cylinder misfires. Looking for threads that address these particular codes ie. 0431, 0421, 0300. 0303, 0306. I have a feeling that these are being caused from a vacuum leak and/or needing a reflash for the ECU.
View 3 Replies