seville sts nortstar
 

I drive a 1997 seville sts with the 4,6ltr nortstar engine. The engine stalls from time to time during idle. Problems occurs very unpredictable when stopping, on f.i. at a traffic light, with gear lever in "D". Engine idles for a while with approx. 650/700 rpm and then stops from one moment to the next. Enggine restarts immediately without problems and runs afterwards normal. Is there a possibility to lift the idle run of the engine a bit? I checked the obd for faults without success. Any ideas what cause the problems? I lif in Germany and the number of experienced cadillac garages is very limited. Any help would be very much appreciated.
Thanks in advance. Ralf

PCM controls idle so it would be hard to raise idle. It could be carbon build up on throttle body. Companies do make throttle body cleaner you want to take MAF off throttle body. Spray cleaner and wipe carbon from throttle plate and bore then reassemble.

Thanks a lot. Tried this over the weekend but without success. Any other suggestions?

Best regards
Ralf

With no codes it tough. Carbon build up in IAC passages, slow IAc valve, High resistance of plug wires, Corrosion/rust on coil tower terminals, Crank sensor and poor grounds. You really need factory service manual and a scanner to own this car overseas. Opel Dealer should have access to GM service information and GM scanner.

Thanks a lot, will try to get the manual. I already contacted a nearby GM-dealer but got, beside of costly part change suggestions, no good advice. Once again thank You
Best regards
Ralf