crazyd Posted June 25, 2014 Report Share Posted June 25, 2014 (edited) Hey all, My '92 has developed a part-throttle, high-RPM 'hiccup' at 4000rpm and 5500rpm. It's a pretty harsh jerk that feels like the ignition is being shut off and turned back on. This started when I had nothing more than a slightly rough idle, and pulled my ICM and coils to take them in for testing. They all checked out, but when I was putting it back together I found a burned spark plug wire near the routing bracket under the front exhaust manifold. I replaced that wire with a spare I had, and put the rest of it back together. The idle smoothed out, but then this hiccup started happening instead. So I replaced all the spark plug wires last night, and it hasn't changed at all. The ICM was tested on some kind of ICM tester at Autozone, I tested the coil resistance myself, and it was the same on all 3 though I don't remember the exact reading. There are no codes. Last I checked, the plugs were in good shape, though I can't imagine how a plug would cause this. Anyone else ever experienced this before? The only other symptom is intermittent hot-stalling at stoplights, though I think that is a separate IAC problem. Edited June 26, 2014 by crazyd Quote Link to comment Share on other sites More sharing options...
jman093 Posted June 28, 2014 Report Share Posted June 28, 2014 It's hard to say for sure. These kind of problems are so hard to diagnose on OBD 1 and its lack of a misfire monitor. IMO, I think you're on the right track testing the coils and ICM, but they can both be bad but not test bad. I've owned two cars that "bucked" or "hiccupped" like you describe and both had a bad pack that ohmed out fine. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted June 28, 2014 Report Share Posted June 28, 2014 (edited) Mine kinda started out like that, then ended up like this: The quick rev-up 2/3 in was wheelspin with the rain, don't mind that. New(used)icm/coils fixed the jumping issues Edited June 28, 2014 by Night Fury Quote Link to comment Share on other sites More sharing options...
crazyd Posted July 8, 2014 Author Report Share Posted July 8, 2014 (edited) So I had two LQ1s in the garage and two sets of ICM/coils that I took to Autozone for testing. I must have mixed them up serendipitously, because replacing the one in the car with the other one I had solved the problem over the weekend. It had that same jumpy tach as in your video, Buck. I say serendipitously, because this saved me from having to troubleshoot that problem once the engine goes into the Fiero, where it's a lot more confusing to sort out problems like that in a swap. You kinda want to know that at least the engine would work in its native habitat before dropping it into a totally different car! Edited July 8, 2014 by crazyd Quote Link to comment Share on other sites More sharing options...
Night Fury Posted July 8, 2014 Report Share Posted July 8, 2014 Glad you figured it out! Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted July 8, 2014 Report Share Posted July 8, 2014 buck....... do you seem to have ignition issues with every vehicle? it seems odd to me. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted July 8, 2014 Report Share Posted July 8, 2014 It is assumed it will happen to every 1g I have, yes. I've pretty much resorted to replacing the entire system at the first sign of failure. icm/coils/wires/plugs. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.