Any ideas for me? 1987 740T
At stops, every 5 to 10 secs the idle drops way down causing the
engine to shudder, then the idle corrects. Engine does not stall.
Runs fine when moving and no problems when in Park/Neutral.
Seemsworse when the engine is hotor when the AC is running.
Have cleaned the TB and replaced the FPR recently.

I welcome and apprecaite any suggestions.

 

Did you clean air flow valve? Is there black soot and smell of very rich fuel from car at idle?

 

Have not cleaned the air flow valve. I will consult Haynes for some guidance there. Any tips on that?
Emphatic YES on the fuel rich smell. Have not noticed soot, but will have another look.
Cheers.

 

also can be a leak in emissons system or a bad part in the system

 

try cleaning the Idle air control valve. It helped with mine. Then go and clean the MAF and then clean the throttle body. If these three things dont fix the problem then look to the the fuel sensor relay thats with the fuses.

 

When you open windows and such, do the revs drop? if so, it might be something eletrical.

 

I pulled off the ACV and a teaspoon or so of clean oil (?) dripped out.
Not sure if that's a sypmtom of another problem.
Used a littlecarb cleaner on the valve,the pins and the connector-which was gunked.

Results? So far so good . . . no idle drop,things have smoothed.
After a nice long freeway drive, I'll see ifsymptoms resurface.

Cheers.

 

I'm still having problems (must have been the placebo effect.)
I am thinking it is temperature related, since it begins only after I've been on the road a while.
There is a strong fuel odor when the idle is struggling.

To properly clean the ACV, do I need to remove the cap and clean the contacts inside?

 

how are the spark plugs and the 02?

 

dont forget the flame suspression devise, aka the pcv valve on other cars