In Reply to: Re: Idle problem (miss or small backfire) with 95 posted by Melby on March 09, 1999 at 20:09:36:
: : : : : I recently had a service done on my 95 M3 at the local dealer. Along with the service, the valve cover gasket was replaced. After I got the car back, there was miss, or small backfire that started to occur at Idle. The car would drive fine, but at Idle it would miss. So I took the car back to the dealer and after numerous test, they concluded it was a problem with the air fuel sensor, and it was replaced. So I get the car back again, but it still has the same problem. I think they may have just increased the idle to compensate for the miss. Has anyone else experienced this problem, and if so, what was the cause? Thanks for any valuable information.
: : : : i would think if it was a miss it would just be the way the engine is retarded. How high does the rpm's run when it missess do the rpms go up or down? write back but it might be a fuel sesnsor and maybe just the engine has a bad calculation when the processess r happening
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: : : There doesn't seem to be a move either way in the rpm's, or if it is, it is very slight. To describe it more, it is most noticeable out the exhaust, and you can even feel it when sitting in the car. Before the dealer replaced the air fuel sensor, it was considerably worst, but the problem has not been fixed totally. One way to decrease the problem was to apply some sort of load to the motor with the AC or just bring the rpm's up to 1000+. Hopefully this helps shed some more light. Thanks for the input.
: : I had the same problem with my 95 M3. Its like a very small back fire or a engine hesitation right? I took it to the dealer 3 times and they said it was nothing and if it was it would have showed up on the computer. Whatever. So now I just live with it. Don't know what else to do.
: : 95 COSMOS
: The dealer also told me that they couldn't find anything else wrong than what I already mentioned. They said to drive it and see if it throws a fault. I have a hard time living with that, especially when it wasn't acting this way before they (the dealer) worked on the car. Has anyone seen a problem like this related to the idle control valve or sensor (I think that is what it is called). Thanks again for any help.
It sounds like You have a lean condition at idle. It could be the Idle control valve or mass air sensor. But I would more likely say it is a slightly plugged injector that just happen to show up at the same time of Your service since no trouble codes showed. Try a heavy dose of Techron and see if that doesn't clear it up. Remember due to EPA standards these things are right on the edge of too lean all the time.