I stored my vehicle for 4 months, unhooked the battery, returned, fired right up and no issues except a very rough idle.

My boyfriend has been working in my car for years and he read about some possible causes for the idle issue.

On a cold start, it’s fine for several minutes, but then it begins to idle roughly and the whole car bounces. If idling a few minutes, it will smooth out, but then go back to bouncing. On idle, if I give it a little gas, it smoothes out or if I put it in Park or Neutral, it’s not as bad, but back in Drive, it’s rough. Running on Premium. No issues once moving.

No leaks between in air filter and the engine. Less than 5 K miles ago, we replaced the air filter and mass air flow sensor and replaced the following within the last two weeks:

New fuel injectors, all 8
New spark plugs, all 8
New coils, all 8

Not one of those made a difference.

Is there something we are overlooking? What can we try before taking it in for an expensive repair?

Thank you in advance.

 

Oops! you already tried what I wanted to suggest. .DTC codes may provide some ideas.
BTW, is Check engine light is on?

 

The check engine light has been on for years. The mechanic said not to worry about it. He has tried to get it to reset after he works in it, with no luck.

 

If false air definitly can be excluded the cause could be a problem with the fuel supply, i. e. Fuel pressure or filter or pump. Or temperature sensor or a crapy new MAF sensor. Or.......

Do yourself a favor and have a qualified diagnosis done with WDS/SDD (genuine OBD equipment).

This costs a little money, but it saves you the unnecessary replacement of spare parts and years of driving around with check engine light on.

Fritz

 

If it is a 1999 you should be trying the x308 .
this part of the forum is for x350 x356 x358 from 2003- 2009 different car

 

Ok. Thank you for pointing this out.

 

I moved to the proper thread.