[dylanAr10]

OK ive been having an issue with my engine running improperly since getting my car at first it never threw any codes and just ran rather rough (Many people said these cars tend to run a bit rough so I ignored it). Well I eventually got a code for the missfire on cylinder 4 and have since been trying to fix the issue. So I've checked rough running in INPA and it is running in the red (Not sure what metric is used for the rough running category) while all other cylinders run between 1.9 - 0.9 on average cylinder number 4 peaks at 4-5 and averages around a 3. But this mostly happens at idle. When I am driving the car Cylinder 4 still goes a little bit into the read but for the most part it behaves normally. Also to note my idle can get super low (On the way home it was running around 525RPM-575RPM). So far I've cleaned the intake valves, replaced the spark plug and switched the coilpack of cylinder 4 with cylinder 2 to confirm it was not the coilpack. The next obvious step is to replace the injector. Just wanted to see if anyone else had any insight as to why it mainly happens at idle and if the injector is really where the problem is as I am starting to tire of throwing money at a problem with no results any would greatly be appreciated!

[luckyblack]

have you changed your spark plugs? Coils, plugs and then injectors for a misfire.

[CanadianTSi]

I had a misfire only at idle and when warm. Still happened on the same cylinder after plugs and coils. New injector cured the problem.

[dylanAr10]

Originally Posted by CanadianTSi

I had a misfire only at idle and when warm. Still happened on the same cylinder after plugs and coils. New injector cured the problem.

Good to know, thanks for sharing! I must say it was so frustrating to pull the plug today and see a perfectly good plug lol! Same thing when It continued after cleaning the intake valves lol. Hopefully the new injector will put this damn issue to bed!

[dylanAr10]

Originally Posted by luckyblack

have you changed your spark plugs? Coils, plugs and then injectors for a misfire.

Yah plugs & coilpacks have been checked. I guess the injector is what I'll do next. I swear if it's still an issue I might lose my mind lol!

[TrollToll]

Just for future reference: plugs and coil problems tend to show up under high boost, high RPM conditions. Fuel injectors tend to show up during cold starts and while idling.

[dylanAr10]

Originally Posted by Yournamehere90

Just for future reference: plugs and coil problems tend to show up under high boost, high RPM conditions. Fuel injectors tend to show up during cold starts and while idling.

Yah no issues with starting just idling but I guess if it's one cylinder that isn't even fully malfunctioning I probably wouldn't have to many issues there.

[808AWD325xi]

I would take a look at the cylinder-selective injector adaptation readings in INPA...MSD80 -> F5 -> Shift-F6 -> F1


Per the engine management training module (page 36):
http://www.e90post.com/forums/attach...8&d=1165592709

Adaptation of the injector opening signal is based on smooth running monitoring of the engine. My guess is that the injection time (einspritzzeit) for cylinder 4 will be skewed when compared to the rest.

[justin895]

Originally Posted by dylanAr10

Yah plugs & coilpacks have been checked. I guess the injector is what I'll do next. I swear if it's still an issue I might lose my mind lol!

Had this issue... Replaced the Coils and Plugs... it went away for a little while and then came back.. replaced the injectors and the issue has been resolved. I was getting misfires on 5 and 6.

[iblue]

Swap the parts between cylinders to see if the problem follows. If it doesn't, it could be an intake manifold gasket blown on that cylinder (that was fun to track down on one of my older cars).

[ferocity02]

Rough idle is typically injectors. Do you have any logs? Looking at the fuel trims can reveal a leaking injector.

[dylanAr10]

Update: Replaced the injector last night and she's running like a well oiled machine! Thanks for the Help everyone and sorry I didn't see the later replies until now. Thanks again guys!

[jwebb335xi]

Originally Posted by dylanAr10

Good to know, thanks for sharing! I must say it was so frustrating to pull the plug today and see a perfectly good plug lol! Same thing when It continued after cleaning the intake valves lol. Hopefully the new injector will put this damn issue to bed!

Another member mentioned injectors for $138 at Advanced Auto... You may want to check that. And, since you have INPA running, the job won't take more than 45 min, most of which is just getting to the injector and putting it all back together. super easy!