94CutlassXtreme Posted October 23, 2006 Report Share Posted October 23, 2006 Alright so my stock 2000 GTP had been running great, but I did notice a low RPM stumble every now and then. Then last week it through an engine light, a P0304, cylinder number four misfire. So I figured hey! plugs and wires should fix this. So I look up the parts at work and the car calls for a Delco Iridium, we were out of em for a picked up Autolite iridium, XP606, and some stock wires. So I bring it to the guy I usually go to cuz I am a lazy fuck. He calls me and says the car has multiple misfires underload. 1, 3, and 6 to be exact. So he told me I needed an ICM. So thats in now and the car doesnt miss. Or so he tells me, and it is not throwing any codes. He told me when he drove it, it felt like its hitting rev limiter. Yea right. So I drive the car and it's fine if you drive normal, but the second you get on it, theres a spot between like 3k-5500 that it feels like its falling on its face, but it breaks outta it once I get some speed up. Clogged Cat? I dont think its the plugs cuz theres no misfire. So whats the deal here? Quote Link to comment Share on other sites More sharing options...
97loudcut Posted October 23, 2006 Report Share Posted October 23, 2006 new plugs and wires and the ICM deffintly should have fixed the misfire problem..Do you smell and rotten odors coming from the exhuast and is your cat ever glowing red after you take it for a long drive? Quote Link to comment Share on other sites More sharing options...
94CutlassXtreme Posted October 23, 2006 Author Report Share Posted October 23, 2006 Thats the odd part, I took it for a beat run when I picked it up to try and see if the cat would glow and it didnt. And I stuck my nose in both tailpipes and couldnt smell anything out of the ordinary. Shit I wish I could do a scan, but I have no scantool. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted October 23, 2006 Report Share Posted October 23, 2006 Autozone or Advnace will usually scan it for free. Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted October 23, 2006 Report Share Posted October 23, 2006 Autozone or Advnace will usually scan it for free. but not a 94/5 Quote Link to comment Share on other sites More sharing options...
customgod227 Posted October 23, 2006 Report Share Posted October 23, 2006 Autozone or Advnace will usually scan it for free. They will only read SES codes, not actually scan the PCM. Wish you lived closer, I could do a scan for you. That sounds odd. So it feels like you just loose some power between 3-5000RPMS? So, what are you mods, usually if it looses constant power between certian RPM's, your PCM is pulling timing to compensate for KR. But if it is stock, it should not be doing that. Quote Link to comment Share on other sites More sharing options...
94CutlassXtreme Posted October 23, 2006 Author Report Share Posted October 23, 2006 Yea I'm stock. I just took it to another mechanic so he could drive it. He thinks the ignition is breaking up as well. I did notice something odd too. Jabbing the throttle half way down creates full boost. Quote Link to comment Share on other sites More sharing options...
customgod227 Posted October 23, 2006 Report Share Posted October 23, 2006 If you have full boost at half throttle...sounds like you could be boost stacking. Something might be clogged. Quote Link to comment Share on other sites More sharing options...
terryk2003 Posted October 23, 2006 Report Share Posted October 23, 2006 FWIW: i've heard copper core spark plugs are the best for our supercharged engines...maybe the new plugs just suck!?... Quote Link to comment Share on other sites More sharing options...
customgod227 Posted October 23, 2006 Report Share Posted October 23, 2006 Def try a colder plug...(I.E Autolite 104's) I gapped mine at 0.50 Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted October 23, 2006 Report Share Posted October 23, 2006 If you have full boost at half throttle...sounds like you could be boost stacking. Something might be clogged. Are you going off the stock boost gauge if so thats normal. My buddy bought his '97 and his had the same thing misfire. We did plugs and wires and it took care of the problem. Are ICM's common on L67s? Quote Link to comment Share on other sites More sharing options...
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