+1 on the carbon blasting. You may not have CEL codes, but you will eventually get misfire ones. Do it every 50-60K miles with a spark plug change, and your engine will thank you. You can do it yourself for about $250 investment (one time), and 4 hours of your time. Pelican Parts has an EXCELLENT walk-through on the procedure.

To get to the throttle body, you had everything removed to do the carbon blasting already.

 

Thanks for the post seandallen! Yes, we have a different method (the method used before the adapter) here: http://www.pelicanparts.com/techarti...n_Cleaning.htm. This saves you money from purchasing the equipment needed to walnut blast. It is still a very effective method. Let me know if you have questions.

 

Hey
I had similar idle problems with my friend R56MCS -08(87 tkm). normally run quit "normal"but idle was very bad,almoust stopped then revs jumps between 1550-2000rpm, then stalled! NO CELS! ,no misfires. we thought,it must be HPFP,NO!,then check timing,allright!,then compression,ok! everything seems normal,but then we find problem!,bad Vanos solenoid!!! we had once cleaned it,but does not check working with powersupply.It is jammed,thats why "dynamic timing",Vanos does not working and makes very bad idle. I hope,that helps you!