Ford Super Duty (1999-2016) :: P0300 Code And Various Misfire Codes For Random Cylinders

New plug on right, lower bank 2 plug on left

Started getting a P0300 and various misfire codes for random cylinders. Truck has 95,000 kilometers so figured I would change the plugs. Several of the plugs on the lower bank on both sides were pretty much toast. Most of the plugs on the top looked good. All of the plugs had a small deposit where the spark hits the ground probe. Picture is typical plug from lower side. changing the plugs should make a big difference in how she runs and eliminate the codes.

Took right on 4 hours same as dealer said it would. I would have got it quicker but it was not a race.

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Golf IV / Jetta IV :: Error Code P0501 Even If Speedometer Is Working

My car (jetta 2002 1.8t) have the error code p0501 even if the speedo is working. I replaced the speed sensor just to make sure.

If I erase the code, and drive no matter how far/fast I go, the check light doesn't turns on. But as soon as I turn of the car and drive again it does comes on.

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Lexus RX 2004-09 :: 2008 RX350 - Check Engine Light For Random Misfire On Cylinders 4 / 5 And 6

I have a 2008 RX350 with 68k on the clock. Received a check engine light for random misfire (P0300) and misfire on Cylinder 4 (P0304), Cylinder ,5 (P0305) ,Cylinder 6 (P0306). Question is what will be causing this to happen. I thought about changing the spark plugs to see if this is possibly the cause. but what else should i be checking?

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Golf IV / Jetta IV :: 2004 - MIL Flashing - Misfire On Cylinder 4

Just dug out my 2004 2.0 Jetta after sitting buried for 4 months. You can see a corner of the wheel there lol, its been a LONG winter. It is my car but my brother normally drives it, and while he is away at uni it just sits.

Anyways, dug it out to start it. Started right up, however after a bit the MIL began flashing. It was running a little rough. Took out my code reader and engine misfire cylinder 4 came up. The rpms are varying by 75~100 every few seconds, however nothing rough. It seemed to rev fine.

Before I put it away I got my brother to put some fuel stabilizer in the fuel. He now tells me that he put some in the oil too since it said "oil stabilizer" as well. It was a seafoam type brand... Not impressed with him there.

My question is could this just be the car waking up? Should I let it run for an hour or two to see if things work out?

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Sonata 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?

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Golf IV / Jetta IV :: Multiple Random Misfires In All 4 Cylinders Came Up / Idle And Boost

I have a mk4 1.8t Gti. Recently I have been having issues with idle and boost. I read the codes and multiple random misfires in all 4 cylinders came up, idle control and the crank, knock, and o2 sensor came up. Shows that system is running to lean as well. I changed the spark plugs and wires, check the coil packs they where done about 1k miles so I expect them to be perfectly fine. When I clear the codes it idles below 9-8k rpms. I also noticed the breather hose coming out of the valve cover into the EGT has a hole melted into it, could this cause any of my issues?

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Passat (B5) :: Random Misfire On Cylinders 3 And 4

Random multiple cylinder misfire according to auto scanner report on a 2002 Passat 1.8L? I have recently changed all belts including the timing toothed belt. I have had this very same problem prior to changing all belts on this car. Mileage is 111,000 ....

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Passat (B5) :: CEL On - Random Misfire On All Cylinders

I went and looked at an 03 Passat 1.8T with 114k miles. I like the car and the price but the CEL is on, returning random misfire on each cylinder with a standard (non VW) scanner. There are no other codes. The car runs beautifully until it idles low with the car stopped or stopping; then you can feel it missing.

The coil packs and controller arms were recently replaced. The timing belt was replaced at 100k. The spark plugs and wires have not been replaced. I don't know whether the coil packs are stock or not, should I ask? The code can be cleared but then it comes back (I'm not sure how long it takes; I could ask).

I've collected this list of possible things to check, based on this useful previous post:

1. Oil overfill.
2. Downstream O2 sensor.
3. Spark plugs and cables.
4. Cam Shaft Adjuster? (maybe? there is no cam shaft code?)
5. Plugged fuel injectors?
6. Plugged catalytic converter.
7. Cam timing?
8. Induction cleaning?

Is this a good list? Are there possible troubleshooting steps not included here? Are some of these superfluous in my situation?

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Golf IV / Jetta IV :: Misfire On Cylinders - Cracked Harness / Vacuum Leak?

I just bought a 05 1.8T Jetta 116,000miles. and need diagnosing it. It misses all the time. Has new plugs I tried two other sets of coils (from my 2.0 a4 and my dads passat) and it made no difference. The SAI was taken out but nothing is blocked off. Also the coil pack wiring harness has cracks on the big brown wire where it goes down along the block. I'm getting these codes on my vag-com.

16687 cylinder 3 misfire
16686 cylinder 2 misfire
16688 cylinder 4 misfire
17766 cylinder 2 open ignition circuit
17763 cylinder 1 open ignition circuit
17769 cylinder 3 open ignition circuit
17772 cylinder 4 open ignition circuit

So am I correct in thinking that it's from the cracked harness? An not a vac leak?

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Golf IV / Jetta IV :: Running Rough And 3 Codes Stored - Cylinders 2 And 3 Misfire

So my daughter's 2000 Golf Mk4 with 160,000 miles on it was running rough and had 3 codes stored - cylinders 2 & 3 misfire and a 411 secondary air injection problem.

Having had the misfire code before I swapped injectors around and the error code moved cylinders with the injectors so I attempted cleaning them and also cleaned the throttle body and intake manifold. At this point car still running rough but also started smoking badly.

Replaced the following items:

- Spark plugs
- Spark plug wires
- PCV valve
- PCV hose
- Fuel injectors w/ remanufactured

Hose reconnected between secondary air injection pump and air intake - previous owner had duct-taped it in when he couldn't get it to seal I guess. I've never heard it run.

Car running better, idles more smoothly, doesn't stumble or stall like it did before, no error codes coming up BUT car smokes a lot and the fumes make me feel sick just driving it a mile.

The car had never smoked like this before, hasn't had a whole lot of love the last year or two but no real problems either so why the sudden smoke?

At first I assumed it was cleaner being burned off but that should have been gone in under a minute and this is on-going. It's bad enough to not only be embarrassing but apparently dangerous as the fumes are bad.

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Golf IV / Jetta IV :: Misfire At Random Times Most Often At WOT

I have a 01 wolfsburg jetta with aw engine code .. I have replaced and gaped spark plugs all 4 coils , DV. As well as fuel filter . Sometimes it runs fine . It misfire at random times most often at WOT. ..and I've noticed almost always when fuel level is low.. installed a boost gauge .. after disconnecting battery to reset ecu it boosts 10psi and runs strong .. however 1 or 2 WOT and it will misfire and then I won't boost over 4-5 PSI .. worst of all I get no CEL not even blinking .. I have also located a leak in the brake booster line . Does this affect it at all? ..

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Lexus RX 2004-09 :: P0355 Error Code And Potential Misfire Codes On All Cylinders

I am getting P0355 error code and potential misfire codes on all cylinders. Engine light and VSC stays on now. Idle is unstable and power is a little jerky at times. I bought a Denso direct ignition coil to replace, however, Cyl 5 looks difficult to access.

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Golf 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.

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Golf IV / Jetta IV :: VR6 - Random Multiple / Cylinder Misfire

Replaced my water pump March 2nd using the "From Below" method. Started the car after and the check engine light was on and water pump was no longer leaking. I drove the GTI to Advance (15 Mins away) it drove fine and I pulled two codes.

P0300 - Random Multiple/Cylinder Misfire
P0301 - Cylinder 1 Misfire

The car pulled and drove normally. The next day the car is misfiring badly. Hesitation and bucks when accelerating until roughly 3k then smooths out.

I will swap my coilpacks and check if the misfire moves as soon as I can get my hands on an OBD2 Scan Tool.

From what I understand about the VR6 :

-The water pump runs off the serpentine belt
-Camshaft timing is controlled by the timing chain.
-Timing chain is not affected by the serpentine belt/pulleys.

Questions :

-Can turning the Crankshaft Pulley affect timing?
-Can that be the cause of the misfire?

24V VR6

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Golf IV / Jetta IV :: No Start - Random Misfire / Stalling And Bad MPG

Well first the exact car I have. 99.5 Jetta 2.0 AEG. It all started with one loud backfire with a stall at a stop light while in neutral. After that it was random stalling and jerking while driving. So I checked my everything and all seemed well. I replaced spark plugs because they where fouled and nasty. Cables are good. They're near new and tested them with a multimeter. Next I checked my injectors and they are surprisingly very clean.

I had also ran seafoam prior to these problems a few weeks before it all started. Next step was new fuel filter. Old one was nasty and black stuff dripped out. That didn't work. So I checked for vacuum leaks with throttle body cleaner. Nothing. Visually threre is nothing wrong under the hood. So today I changed the fuel pump. Went for a test drive all seemed well. Can out of the bank. Then it won't start. So I wait like normally. And it normally gets me home. Nothing. Will sometimes start but if I'm not holding the gas it dies. I don't know what to do. My only other thing I can think of is the coil pack.

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Golf IV / Jetta IV :: 2000 VR6 Random Misfire In Cylinder 2 And 5

About a month ago my wife's 2000 Jetta with the VR6 engine in it started acting up and throwing codes. The codes it threw were for random misfire, misfire in cylinder 2, and misfire in cylinder 5. Starting out, we changed spark plugs, fuel filter, and made sure the injectors were clean.

The problem didn't go away so we water tested the coil and wires, but they passed that test. The wires were quite old and out of spec, while the coil was in-spec across all terminals, according to the vehicle service manual, so we installed some new OEM leads this weekend. While installing the leads we noticed a disconnected vacuum line and reconnected that as well.

The vehicle was driving great for two and a half days, then today while I was sitting at a stop light, it started missing really badly and felt like it was going to kill. It did this for about 5 seconds, then recovered and ran smooth for about 5 seconds, before getting really rough until I started driving when the light changed. It didn't do it when I drove it a few hours later at all. This episode didn't throw any codes either.

What could be causing this issue? Would the MAF cause the intermittent missing, or is it possible that the computer is going bad?

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Golf IV / Jetta IV :: 1995 - Random Multiple Cylinder Misfire?

I have a 1999.5 Jetta VR6 12v, last week the car would not start. After some tests I determined the coil pack had gone bad. Replaced the Coil with a brand New aftermarket German made coil. Now 1 week later, driving at highway speed CEL came on, started to flash and obviously misfiring again. Ran Codes and now im getting these DTC's:

1)random multiple cylinder misfire detected p0300

2) cylinder 4 misfire detected p0304

3) ignition coil output 3 electric malfunction p1395

4) cylinder 3 misfire detected p0303

has this new coil gone bad already after a week?

New issue?

Plugs were replaced less than a year ago, wires were apparently replaced by previous owner about 2 years ago now. Crank sensor replaced less than a week ago...

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GMC - Sierra :: 2004 - Code P0300 Random Misfire While Under Load

2004 GMC Sierra 2500 HD, 227,000 miles 6.0L V8.

While driving up hills or increasing load, the CEL will flash multiple times, I pull over as I know CEL flashing is not good. I turn the truck off, allow it to sit for a few minutes, whip out the code scanner, only code that was there happens to be P0300. Truck has poor MPGS, idles rough, loss of power. this happens every time I drive this vehicle as I use this truck to pull my trailer that weighs around 4000 lbs. Problems come and go. Some days I can drive the truck for an hour with no problems, come up to a red-light, BAM, CEL is flashing, truck is bouncing side to side due to the poor idle, other days this happens while sitting in the parking lot of my job with the ac on.

Truck has been to the shop several times as I'm no mechanic. Parts replaced are as follows:

- Fuel pump
- Throttle Body
- All plugs
- All wires-All Coils
- Intake Manifold Gasket-
- Battery
- Sensor 1 Bank 1 O2 Sensor
- Sensor 1 Bank 2 O2 sensor

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Santa FE SM (2001-06) :: 2004 3.5L V6 - Random Misfire Code P0300

I have a 2004 Hyundai Santa Fe 3.5L V6 when i was driving a couple of days ago the check engine light flashed and after a while it stayed on the codes are P0300 which is a random misfire as well as a misfire in cylinder 2, 4 and 6

I replaced all 6 spark plugs and the 3 spark plug wires still the same issue. The car hesitates when accelerating when i accelerate it looks like it wants to stop the rpm goes to almost zero and then it moves and so on. the rpm goes up and down like crazy.

Sometimes it won't move past 1000 rpm I'm moving 60mph and still on 1000rpm and sometimes it works just fine like there is no issue at all. When idle the car is fine and everything seems normal it stays on 900rpm. The car has 158K miles on it.

I uploaded a video to show you what's happening to the tachometer when I accelerate [URL] ....

I'm on a limited budget I'm thinking of changing the ignition coils but i want to make sure that's what is causing the problem first because i spent 200$ to change spark plugs and wires and the mechanic didn't fix the issue.

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