Mace1647545504 Posted December 22, 2017 Report Share Posted December 22, 2017 Says it's random cylinder misfire car starts but runs extremely rough ...soooo I'm thinking its ignition related. I will begin by pulling each plug wire and see if I'm getting spark on all, but after that I'm a bit lost. I would then think icm but how would I test it? Could it be a maf or would that throw a different code?Any other ideas? Thanks mace Quote Link to comment Share on other sites More sharing options...
Green Bastard Posted December 22, 2017 Report Share Posted December 22, 2017 Been through this a couple times, most likely the coils. I have a pontiac with the 3800 in it, if you like I could stop by this weekend and you could throw my coils on to test. Quote Link to comment Share on other sites More sharing options...
Cordell Posted December 22, 2017 Report Share Posted December 22, 2017 Been through this a couple times, most likely the coils. I have a pontiac with the 3800 in it, if you like I could stop by this weekend and you could throw my coils on to test. Yeah this most likely. Spray some water on the engine while it's running and see if anything starts arcing. A scan tool that'll show which cylinder(s) is misfiring (live data) would give you a big step toward where to look. Quote Link to comment Share on other sites More sharing options...
Mace1647545504 Posted December 22, 2017 Author Report Share Posted December 22, 2017 Been through this a couple times, most likely the coils. I have a pontiac with the 3800 in it, if you like I could stop by this weekend and you could throw my coils on to test. I appreciate the offer but this weekend is blink for me. We have family over for a huge Italian dinner. I'm off work next week and will take a run at it . Again Thank you very much mace Quote Link to comment Share on other sites More sharing options...
STEVE-O Posted December 22, 2017 Report Share Posted December 22, 2017 3800 is known for crank shaft sensor going bad also Quote Link to comment Share on other sites More sharing options...
xlr8tn Posted December 22, 2017 Report Share Posted December 22, 2017 Have you checked fuel pressure also? Miles on fuel filter? I'd start simple first. Gm is not known for their high quality fuel pumps. Quote Link to comment Share on other sites More sharing options...
2 Sweet Posted December 22, 2017 Report Share Posted December 22, 2017 Here's where I would start.......Take off the coil packs, clean up the points and also clean up where they sit on the ICM with a wire brush or whatever, wipe it with dialectic grease and reinstall. Takes less than 5 minutes. MAF would throw a different code. It could be the CPS but I would definitely start with the coils and go from there Quote Link to comment Share on other sites More sharing options...
Buck531 Posted December 22, 2017 Report Share Posted December 22, 2017 (edited) Plugs/wires/ICM/hole in piston. Edited December 22, 2017 by Buck531 Quote Link to comment Share on other sites More sharing options...
Mace1647545504 Posted December 22, 2017 Author Report Share Posted December 22, 2017 So my son was off work and he started the car pulled the wires off the plugs and found something weird. 3 of the 6 plug were rusted, I thought they may just be discolored so when I got home I pulled the wires and sure enough they are rusted. What might cause the plugs to rust? Would replacing the plugs fix the problem short term and yes the boot plugs showed rust in them. What do you think?? Thank you for the input Quote Link to comment Share on other sites More sharing options...
Cordell Posted December 22, 2017 Report Share Posted December 22, 2017 Just the spark plugs? or are the coil towers rusted? Rusted coil towers are pretty common. Just replace all the effected components. Quote Link to comment Share on other sites More sharing options...
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