RacerX Posted March 27, 2005 Report Share Posted March 27, 2005 My car, a 1996 Z34 with the LQ1, keeps getting a misfire on cylinder #4. Originally, assuming this is purely an ignition problem, I went after the plugs, wires and coils. I have been able to eliminate sporadic powerloss and a tendency to buck at low rpm with the TC locked, but a misfire at idle persists with a code pointing to cylinder #4. Got any ideas? Quote Link to comment Share on other sites More sharing options...
White93z34 Posted March 27, 2005 Report Share Posted March 27, 2005 did you replace the ICM with the coils as well? i take it when driving it smooths out? Quote Link to comment Share on other sites More sharing options...
RacerX Posted March 27, 2005 Author Report Share Posted March 27, 2005 The ICM is still original, and the idle does eventually become smoother after about an hour of driving it. EDIT: I find it strange that when it gets bad enough to actually set the SES light, the idle suddenly becomes smoother. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted March 27, 2005 Report Share Posted March 27, 2005 The ICM is still original, and the idle does eventually become smoother after about an hour of driving it. EDIT: I find it strange that when it gets bad enough to actually set the SES light, the idle suddenly becomes smoother. If the SES light comes on, the computer might be retarding the timing or something to reduce misfires.. I think that's how it works. Quote Link to comment Share on other sites More sharing options...
Crimson Fury Z Posted March 27, 2005 Report Share Posted March 27, 2005 take it from me, replace the icm, i had to hit the gas hard at start up to even get a code. mainly if it isn't bad, it wont throw it. don't delay like i did and get stranded . Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted March 28, 2005 Report Share Posted March 28, 2005 I would take the ICM out and take it to your local parts store and get it tested. Here in Canada, we have PartSource and they test them for free. That way you know for sure if its your problem. Quote Link to comment Share on other sites More sharing options...
Crimson Fury Z Posted March 28, 2005 Report Share Posted March 28, 2005 yes! forgot about having it tested. make it so RacerX Quote Link to comment Share on other sites More sharing options...
RacerX Posted March 29, 2005 Author Report Share Posted March 29, 2005 Is it likely for the ICM to malfunction only at idle and have no impact on performance? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 29, 2005 Report Share Posted March 29, 2005 My old 3.4 does this... Quote Link to comment Share on other sites More sharing options...
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