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.