I've got an idle problem on my 1990 240 with 167k miles on it. I recently had the injectors cleaned professionally with the hope that it would smooth things out... When the engine is started from a cold start, the idle seems quite smooth, no engine shake at all, and only a slight "skip" once in awhile. Once the car warms up, the engine shake at idle returns.

Here's what I've done:
1) Replaced IAC with a known good one
2) New FPR installed
3) New fuel filter
4) repaired vacuum leaks in accordian hose from AMM
5) Fuel pumps are both running fine.
6) Throttle body cleaned, new gasket.
7) ECU temp sensor
8) Intake manifold gasket
9) Airbox thermostat replaced
10) O2 sensor (changed with the cat converter)

The car runs strong at cruising speeds, thankfully the clean injectors seem to give more power (although my main reason for the clean was the idle).

Has anyone had a similiar experience with the idle/smoothness changing from cold engine to warm?? What was your solution??

On a side note, I know that there are significant (to me) deposits in the combustion chamber/valves. I plan on running the "water clean" recommended in the FAQ to hopefully clean things up and then a can of BG44K for good measure. Two questions: which vacuum hose/port is best to use for the water clean and is it wise to do both the water clean & BG44K (in the tank) right after one another?

Thanks for your advice,
Zuda