Drummer Posted April 15, 2008 Report Share Posted April 15, 2008 when i first start my car up it idles smoothly but after it warms up it starts to form a miss when listening to the exhaust. Also when i'm in 5th gear and at 1000 and step on the gas the car starts shaking and it also back fires until you get up to 2000rpms or higher, then it just misses once in a while. I was thinking it could be plugs and wires, or even coil packs, but it's weird that it does it after it warms up, which then makes me think motor. If anyone could wager a guess that would be great. Quote Link to comment Share on other sites More sharing options...
Q-Ball Posted April 15, 2008 Report Share Posted April 15, 2008 I forgot to ask you when was the last time you changed the plugs and wires? If its been long or you cant rememeber, I'd start there. Maybe there is a small crack in one of your wires? Quote Link to comment Share on other sites More sharing options...
Venom Posted April 15, 2008 Report Share Posted April 15, 2008 Sounds like maybe a ICM or coilpack or maybe even fuel pump. If you have one thats bad, a symptom could be once they get hot, they start failing. If you have access to a fuel pressure tester, I would see what PSI you are running once the car is warm and starts acting up. Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted April 15, 2008 Report Share Posted April 15, 2008 Exactly what happened with my Cutlass, it would run fine until it got to operating temp then it would run like shit. Then it would overheat too, which always boggled my mind Either ICM or a coilpack, I'm guessing ICM though. Quote Link to comment Share on other sites More sharing options...
olds cutlass Posted April 15, 2008 Report Share Posted April 15, 2008 Old electronic parts will start breaking down when they get hot. I would think that its one of the coil packs. After its warmed up get a tall can of compressed air, turn it upside down and blow across the coil packs to cool them down and see if makes a difference. It could also be the base that they plug into. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted April 15, 2008 Report Share Posted April 15, 2008 Old electronic parts will start breaking down when they get hot. I would think that its one of the coil packs. After its warmed up get a tall can of compressed air, turn it upside down and blow across the coil packs to cool them down and see if makes a difference. It could also be the base that they plug into. I may just try that. I have been experiencing very similar problems. Quote Link to comment Share on other sites More sharing options...
Drummer Posted April 17, 2008 Author Report Share Posted April 17, 2008 well i changed my ICM and even a coil pack i was too lazy to change before and still i can hear a putt putt putt sound. tom. i have to look at the back 3 spark plug wires and change the back 3 while i'm at it. Is it possible for a fuel injector to do this also when it's going south or is screwed up? Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted April 17, 2008 Report Share Posted April 17, 2008 could be, but unlikely given the conditions, imho. Quote Link to comment Share on other sites More sharing options...
Drummer Posted April 23, 2008 Author Report Share Posted April 23, 2008 well i've changed everything i can possibly think of. changed the ICM, coil packs, plugs, and wires. The car still misses and backfires below 2000 rpms. misses sometimes constantly or once in a while, and backfires once in a while. This has been going on for 2 years and i'm finally wanting to get it fixed. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted April 23, 2008 Report Share Posted April 23, 2008 injectors? Quote Link to comment Share on other sites More sharing options...
Drummer Posted April 23, 2008 Author Report Share Posted April 23, 2008 i was thinking injectors also, but the backfiring makes me think other. I'm gonna run seafoam through it to see what that does. should i use seafoam or just an injector cleaner. what's your opinion? Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted April 23, 2008 Report Share Posted April 23, 2008 Im having a stumble / misfire on my cutty international at idle and light loads. Im thinking of running some strong injector cleaner through it. I've swapped everything out. CPS, ICM, coils, wires, plugs, swapped the entire fuel rail/ FPR / injectors assembly from my parts car. Has the car been sitting awhle? Or run right empty recently? Mine has. I'm thinking maybe some dirty or old gas got stirred up when I filled up after I bought it. That and do a compression check. Quote Link to comment Share on other sites More sharing options...
jman093 Posted April 24, 2008 Report Share Posted April 24, 2008 If you get really stuck you might try a crank sensor. I was battling missing and stumbling issues for several months and could not figure it out. I put a Tech 2 on that car a couple times and it never showed a loss of crank signal,, but an old mechanic suggested I try one anyways. He said they were all junk our cars. For $20 I figured it to be worth a shot and it fixed it. My car's pushing a quarter million miles and is running like new again. My mileage also bumped up. I had been making around 26 and the last couple times I filled up I made 28 and 29. I really don't know if it's a crank sensor, but if nothing else seems to work.... Quote Link to comment Share on other sites More sharing options...
93CutlassSupreme Posted April 25, 2008 Report Share Posted April 25, 2008 How old is the O2 sensor? Quote Link to comment Share on other sites More sharing options...
Drummer Posted April 26, 2008 Author Report Share Posted April 26, 2008 The O2 has been on since 04 when i got my Z. Quote Link to comment Share on other sites More sharing options...
93CutlassSupreme Posted April 26, 2008 Report Share Posted April 26, 2008 O2 sensors can also cause engine vibrations (misses) without throwing a code. Quote Link to comment Share on other sites More sharing options...
Hal H Posted May 1, 2008 Report Share Posted May 1, 2008 It's a process of elimination. any idea on the condition of plug wires? check the idividual coils for continuity/resistance. Since you have removed the coils to check the primary and secordary windings: next, have the ICM checked (I had my original go bad years ago). It would run okay when cold, but warmed up, almost 1/2 the cyls would misfire, barely run. Then intermittently, it would clear up, then go back to misfiring. Some of the prior posts indicate these ICM's can be tested? Never had a CPS sensor go bad, but usually those fail when the get hot (no signal), and after cooling down, the engine will run again. Typically behavior for CPS, regardless of make of car. Quote Link to comment Share on other sites More sharing options...
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