960 rough idle, backfire

960_paul · Post by **960_paul** » 14 Oct 2009, 22:29

I have a 1997 960 that has a rough idle at start up, accompanied with backfiring when given gas in neutral. if left at an idle, it will begin "bouncing" the rpm's up and down slightly after a few minutes. it drives fine, but lacks power upon heavy exceleration until the engine "catches up" to itself. The problem started when I pulled the spark plugs and noticed that not only were they massively worn, but the gaps were about double what is called for. I then changed the plugs, as well as wraping the shafts on the coils with electrical tape, as they were all slightly cracked and I don't have the money to replace them. after reinstaling the coils, the check engine light came on and the car began feeling as though it was going to stall when the ignition is turned. This tends to smooth out once the engine warms and the car is driven, but presents itself once again when the car is started again. could this be a problem that the computer may reset after being driven seeing as how worn the old plugs were, or might this be another problem? also, I just replaced the head gasket myself, but the problem was presenting itself before I did the job, as well as after. thanks for any help you guys might be able to give me!

Post by **billofdurham** » 15 Oct 2009, 11:38

The first job is to find out what codes have been set to activate the Check Engine Light (CEL). If codes are in the system the ECU will 'assume' there is a problem and compensate for it. This could be the cause of the poor running.

Read, or have read, the codes and clear them then run the car to see if the CEL comes on again. Quite often the codes won't return and you will have nothing else to do. If the codes do return post them here for advice on what to do.

Bill.

Schumi 1 · Post by **Schumi 1** » 10 Aug 2011, 08:07

did you ever solve your problem ?