Random misfire P0300 code

[crucianpilot]

Ok gents need some advice please. I've got a random misfire occurring and can't find the cause. Here's what's been done so far. New NGK tr6s gapped at .28, checked all cops, vacuum lines all checked and dealer did the relearn profile with their ids tool. The last one seemed to correct the issue but it returned. Here what's interesting: I ony get it when the car is idling and in gear at a constant rpm. Doesn't happen accelerating or decelerating and also not in 6th at highway speed (65-70). Thought it might be bad gas but been through 2 fresh tanks already. Any suggestions before I take it back to the dealer.

 

[turbo]

What mods do you have? And please, don't be fooled by some "tuners" the chance of bad gas these days is almost impossible. Why you ask? Because only people who have aftermarket tunes are ever told bad gas could be the problem. Its almost always, a bad tune

 

[2011 gtcs]

If you're not pulled down than you should definitely be running the OEM plugs.

 

[VNMOUS1]

Ok gents need some advice please. I've got a random misfire occurring and can't find the cause. Here's what's been done so far. New NGK tr6s gapped at .28, checked all cops, vacuum lines all checked and dealer did the relearn profile with their ids tool. The last one seemed to correct the issue but it returned. Here what's interesting: I ony get it when the car is idling and in gear at a constant rpm. Doesn't happen accelerating or decelerating and also not in 6th at highway speed (65-70). Thought it might be bad gas but been through 2 fresh tanks already. Any suggestions before I take it back to the dealer.

How large is your CAI? Misfires can come from a lot of things. You can datalog it and see them but you can't really isolate whether it's electrical or mechanical.

The dealer didn't 'correct' it...the tool cleared the DTC.

I haven't seen your car in a while. Shoot me a list of all the mods if you'd like to [email protected]

The TR6s are fine....you really don't need them gapped that tight with a pulley. I think you have a stock blower, right? Gap them to about 032.

bj

 

[VFORCEJOHN]

I had a low end stumble at idle when warm (tach light is open to 7g and no codes) I ended up installing the OEM plugs back in it and it's gone. I tried gapping from .035 to .025 with no change.

Was it really necessary to replace them with a TR6??? IT didn't seem th change anything but adding this issue. so I'll stay with the OEM plugs.

 

[crucianpilot]

Sorry, forgot to list my mods. Currently running vmp 67 tb, jlt 127 CAI, vmp 2.4 pulley and mrt off road hpipe.

 

[Bobbyblaze]

When my car threw a misfire code it was because of fouled plugs. Maybe switch out your plugs, they are cheap and should be changed every 3k or so.

 

[crucianpilot]

The plugs are brand new.

 

[Van@RevanRacing]

We've been observing on multiple customer cars that these engines like a colder spark even over the NGK TR6. Many of my customers have been switching to NGK TR7IX plugs gapped at .028

To the OP do you have any oil separators on the car? If so inspect all lines and fittings for cracks or splits in lines or hoses as well as fittings. It only takes the slightest amount of unmetered air after the MAF to throw a misfire code.

 

[crucianpilot]

Will do Van, thanks.

 

[sykb47l]

13-6 kit and I too am running the TR7IX plugs now.

 

[biminiLX]

We've been observing on multiple customer cars that these engines like a colder spark even over the NGK TR6. Many of my customers have been switching to NGK TR7IX plugs gapped at .028

To the OP do you have any oil separators on the car? If so inspect all lines and fittings for cracks or splits in lines or hoses as well as fittings. It only takes the slightest amount of unmetered air after the MAF to throw a misfire code.

Good advice and I agree with the change from TR6s.
I run NGK BREF7 spark plugs, same heat range but a non-projected tip electrode.
Personally I think heat range 7 is HOTTEST we should use, if pump gas the COLDER 8s might be a better option depending on gas.
-J

 

[2011 gtcs]

Do you guys know if the NFK BREF7 plugs are Platinum or still copper?

 

[Van@RevanRacing]

Do you guys know if the NFK BREF7 plugs are Platinum or still copper?

Copper.

 

[Ghoust]

Resurrecting this old thread. I have been getting a P0300 over the past 10 months. Within the last 200 miles, I have swapped out to brand new plugs, TR6s, gapped at .28 and new coil packs. Still this morning, I threw a P0300 at constant RPM crusing at about 35mph.

not sure what else to do here. Any other remedies guys? My mods are in my signature.

 

[Lillou74]

I had a similar issue earlier this spring. After four weeks it ended up being corrupted files in my X4 Tuner. I updated my handheld while car was tuned, you're supposed to have car tuned stock with X4 being unmarried. So the dealership reflashed my pcm with stock Tune then I got new tunes from my tuner due to files getting corrupted during update. Worth a try....

 

[red500]

I am also getting random misfire codes then I started getting p0308 code and some times p0302
so I moved the coil plug to 4 from 8 and started getting p0304
but today I was getting p0300 and p0302 and p0308 so I am going to swap out the coil packs and move to a colder plug maybe a ngk tr7ix and see if that fixes it

mods are 10% CRK/2.5 UPPER/VMP 67MM/VMP ELBOW/Stainless works LT/jtl cai 123mm

 

[Robot_trainer]

We've been observing on multiple customer cars that these engines like a colder spark even over the NGK TR6. Many of my customers have been switching to NGK TR7IX plugs gapped at .028

To the OP do you have any oil separators on the car? If so inspect all lines and fittings for cracks or splits in lines or hoses as well as fittings. It only takes the slightest amount of unmetered air after the MAF to throw a misfire code.

Just my experience with this...for some reason my engine did not like the NGK BREF7 plugs. I tried various gaps from .028-.034 and kept getting a random stumble until it finally threw a code. I replaced them with equivalent NGK V power plugs and it was better but still had faint skip and threw another code after a few weeks. I finally went back to the Iridium plugs gapped at .034 (Autolite XP103) and it now runs great. Smooth, no pinging, no missfires and no codes. This is with the CAI and larger throttle body and corresponding tune.

 

[Robot_trainer]

We've been observing on multiple customer cars that these engines like a colder spark even over the NGK TR6. Many of my customers have been switching to NGK TR7IX plugs gapped at .028

To the OP do you have any oil separators on the car? If so inspect all lines and fittings for cracks or splits in lines or hoses as well as fittings. It only takes the slightest amount of unmetered air after the MAF to throw a misfire code.

Just my experience with this...for some reason my engine did not like the NGK BREF7 plugs. I tried various gaps from .028-.034 and kept getting a random stumble until it finally threw a code. I replaced them with equivalent NGK V power plugs and it was better but still had faint skip and threw another code after a few weeks. I finally went back to the Iridium plugs gapped at .034 (Autolite XP103) and it now runs great. Smooth, no pinging, no missfires and no codes. This is with the CAI and larger throttle body and corresponding tune.

 

[red500]

just an updated found out what my problem was after changing both the coil packs and the spark plugs i was still getting the misfire

i used my sct to do a relearn crank position and the problem cleared up.

once again thxs revalution automotive for doing your F***ing job. im so done with that shop.