[at3090]

Hello, I drove my car about 3 hours and stopped, go in the car again and started to drive back, after about 20 minutes I did a little pull(about 80% throttle) immediately a drivetrain malfunction pops up. I look at the code and I get cylinder 4 misfire and then injector deactivation. I clear the code and it runs perfect the whole way back. Thinking it would be something small I changed the spark plug and no change. I move the coil packs around and still nothing. I had a MHD stage 2 tune but removed it. That caused the misfire to not come up unless the engine was under high load. If I keep it in manual mode and slowly increase rpm it won’t misfire. But if I just jab the throttle and it downshifts it causes a mis. I had an e-30 tune but removed it and filled up with 91 octane. Is there something easy that I am missing or will I have to take it somewhere to have them check it out? Any help is greatly appreciated

[SuperLomi]

Off the top of my head my thoughts are:

1) check cylinder compression just to rule it out, but I suspect it’s:
2) possibly a faulty fuel injector - maybe not flowing enough fuel at high load or slow response causing a lean condition.

[at3090]

Originally Posted by SuperLomi

Off the top of my head my thoughts are:

1) check cylinder compression just to rule it out, but I suspect it’s:
2) possibly a faulty fuel injector - maybe not flowing enough fuel at high load or slow response causing a lean condition.

Is there anyway to check an injector or clean it or would I have to just replace and code it?

[SuperLomi]

You could try running a bottle of Techron through it I suppose.

As for diagnosing the injector itself I’m not sure.

[thejeremyman9]

Anything weird in the datalogs?

[at3090]

Originally Posted by thejeremyman9

Anything weird in the datalogs?

I did take a few logs, no full throttle just because it didn’t sound good once it started misfiring. But everything looked completely normal, no timing corrections or anything. But I did figure it out, when I swapped spark plugs I didn’t use a universal joint and I think I broke a the spark plug. I took it back out and it started to follow the spark plug, then the other I switched it with was also bad. Then a day later the coil went bad. But it’s all good now (I think). I literally never floor my car so I have no clue how long it’s been like that. Since both times it started misfire was with people other than me driving. But so far so good, it pulls good now no misfires at all in datalogs.

[at3090]

I also want to say that there was zero clue of a bad spark plug or coil at idle or under light-medium throttle. Once the code was cleared the car ran absolutely flawlessly. Just really weird since nothing like that has ever happened to me. I ordered a whole coil plug-spark plug kit from fcp euro so I can replace them all. I do like how easy it is to change the spark plugs on these inline engines.

[thejeremyman9]

Cracking plug is very common when you install plugs without the ujoint, the cracks are usually not able to be detected by just looking at them.