My idle is rough on my 1994 bmw 325i. I've change the main relay. Oil change. Spark plugs it's black black . Same thing. Check fuel line, fuel pump. All working fine. Idle is rough applying the gas pedal it doesnt go back.

  I'm going to offer you some things to look at but before I do that, I would like to remind you that, in My Profile, I'm a Parts Specialist, NOT a Tech, okay?
  IF I'm reading your inquiry correctly, you say the idle is rough, correct? Then you state you changed the Main Relay and changed the oil. Then you state the Spark Plugs are Black. Then you state "Same thing". What Same Thing? You then state that fuel line, fuel pump are good. Then you make a statement I don't understand, "Idle is rough applying the gas pedal it doesn't go back".?
  Okay, To something I understand, the spark plugs are black. This indicated an Over Rich condition which means the intake charge going into the engine is too rich... too much gas and not enough air. Have you checked the Air Filter to see if it is plugged up? Have you had the computer scanned to see if there may be a problem with the Oxygen Sensors? "Idle is rough applying the gas pedal it doesnt go back". IF you mean the engine doesn't go back to normal idle, it could be the Idle Air Control Motor. Have you checked that?
  The first thing I'd do is put in a new set of spark plugs, check the air filter and see how it runs. IF it runs like it should, wait and see. IF they carbon up quickly, then I'd begin looking into some of the things I suggested.
  Tiny, I'm NOT a Tech but I'm trying to help you solve you problem. I hope this gives you some direction. IF this doesn't help, get back with me and I'll give you a link to a web site that my be able to help you OR you can contact a real Tech on this site.
Good luck,


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Skip Bollinger


Heretofore, I will NOT answer any mechanical question. I am not qualified and can only offer speculations. You are better served by others that are true Techs. With that being said, please only ask about parts and locating obsolete Auto Parts. Thank you. I have the ability to locate quite a few mechanical parts for American made vehicles fron the 1900`s to present. Some are OEM and some are aftermarket. This would include engine, brake and chassis parts. Body parts and trim are VERY difficult to find but you may inquire. If you need assistance in repair, I have illustrated books for major American manufacturers that show some illustrations BEFORE 1974. If needed, I can supply repair manuals for your specific vehicle. PLEASE REMEBER I'M A PARTS SPECIALIST, NOT A TECH!! Thank you.. Skip


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