My car has been idling rough since i bought it.. The rpm drops down really low.. The car sputters.. It has plenty of power when I Go WOT, there's no hesitation, it runs great..But when its idle, its shaky.. Im afraid that one day it may turn off on me in the middle of traffic..

Before I get flamed..

Ive already

1.changed all the spark plugs.
2. Replaced air filter (was super dirty)
3. Cleaned the throttle body.
4. Seafoamed from the brake line and fuel tank.

I didnt notice any difference at all from when I first bought the car.
It still idles rough..

Any ideas on what it could be???

Oh yea,
and I DO have oil in my spark plug holes...
2 of them to be exact.. The ones in the rear side of the engine...
Could this be the reason for my rough idle??

 

could it be the coils?

 

Could be anything. Take it to a shop and have them look at it. We can't perform an "internet diagnostic" on something like this.

And yes, it could be your sparkplugs and valve cover gasket.

You need to replace your valve covers. Both of them. And it's going to cost you $300 each.

 

is your battery ok? try getting your battery tested

 

If the air filter was as dirty as you say I'd clean the MAF sensor and PCV valve.

 

Sounds like you need to start there....how good is a spark plug if it coated with oil?

 

I'M having the same problem only that my car was driving well I was told to change the spark plugs i did and also clean the throttle body and now my car has a service engine soon light and when I try driving it it starts blinking. I got the idle down a little but it is rough I have a g35 2004 coupe

 

check for codes, i don't think the cylinders with those spark plugs are firing or are probably misfiring really badly. try disconnecting/switch coil packs and see if that solves anything.

but the first step would be to check for codes. easy and most of the times free.

 

I had the same exact problem and it was a small vacuum leak. Buy some carb cleaner and spray around the engine. When you hit the vacuum leak, you will hear the engine sputter a bit.

 

ok I will try that Saturday I don't get it my car was working very well man I will let you know thank you all for your help or after you find the leak then what

 

didnt see a thing mentioned on IDLE reset...

ill bet 100 bucs that will solve your problems.

http://www.nicoclub.com/archives/g35...-learning.html

 

I have the same issue with my 6mt but only when the a/c is off. When the a/c is on the car kicks the idle up higher so its not rough.

I have done all of the above including
spark plugs
seafoam
MAF cleaning (I do it occasionally anyway)
I have looked at it with a scanner to see if any of the live data parameters were weird
I have disconected the battery and reset the ecu like that

I can't get the car to let me reset the ecu or idle with the pedal reset procedure. A couple years ago I reset the ecu using the pedal trick after doing a spacer install and had no issues doing it. Now when I try to do it or the idle reset, it wont work. Also I don't think it's because I am timing the sequence wrong. I have done it in the past and tried at least 20 times now and can't get it.

I am sure the idle reset would do the trick IF I could get my car to do it.

 

I dont believe idle reset is the cause for OP's issue since he has a check engine light and i dont think idle reset throws any codes

 

except the OP didn't say he has a check engine light. Someone else chimed in saying it and their's sounds like a different problem since it only happened after they changed the plugs and cleaned the tb. The OP and I have always had this problem and changing the plugs and cleaning the TB had no effect on the issue.

 

I have the same problem only my rpms don't move. It's like the ac compressor kicks on and the whole car vibrates for 20 seconds then it turns off for like 3 seconds and kicks back on. Very weird and once I hit the gas it drives perfectly. I only noticed it when I put my stock exhaust/cats back on. I did ECU reset but maybe I'll try all of the resets today..