geowarr Posted November 3, 2006 Report Share Posted November 3, 2006 Help!!! I am stumped. I have a bad misfire on my 03 SS. I had a friend connect his handheld to it and we drove. It only does it on high rpm. Misfire on cylinder 6. I replaced the plug and coil. Still does it. The only mods i have are high flow mufflers and PCM4less tune. Any ideas where to go next? If it was an injector, wouldn't it do it all the time? HELP!!! Quote Link to comment Share on other sites More sharing options...
SSThunder Posted November 3, 2006 Report Share Posted November 3, 2006 Help!!! I am stumped. I have a bad misfire on my 03 SS. I had a friend connect his handheld to it and we drove. It only does it on high rpm. Misfire on cylinder 6. I replaced the plug and coil. Still does it. The only mods i have are high flow mufflers and PCM4less tune. Any ideas where to go next? If it was an injector, wouldn't it do it all the time? HELP!!! <{POST_SNAPBACK}> maybe bad gas . Mine misfired once and it turned out to be bad gas. Are you running at least 91 octane? Quote Link to comment Share on other sites More sharing options...
trickmob Posted November 3, 2006 Report Share Posted November 3, 2006 I had same problem.Change fule filter and get a purge done.Fresh gas Quote Link to comment Share on other sites More sharing options...
BenKey Posted November 3, 2006 Report Share Posted November 3, 2006 New wires? If you have it narrowed down and you think it may be an injector or wire, just swap it with one of your others and see if it moves to the swapped cylinder. Changing an injector around just takes a few minutes. Quote Link to comment Share on other sites More sharing options...
.justin. Posted November 3, 2006 Report Share Posted November 3, 2006 (edited) One thing that needs to be mentioned is that with every PCM Forless tune I've seen, the Crank Relearn MIL is disabled, so you never know that one is needed. With the Crank angle sensor being used largely to detect misfires, it very well could be that the PCM is inaccurately reporting the misfire. If you haven't done it, I'd recommend getting a relearn done, as you'll never know that you need it. Edited November 3, 2006 by .justin. (see edit history) Quote Link to comment Share on other sites More sharing options...
Bonj87 Posted November 3, 2006 Report Share Posted November 3, 2006 i had that same thing happen on cylinder 3 earlier this year..and it was an injector just after that, my cats had to be replaced Quote Link to comment Share on other sites More sharing options...
geowarr Posted November 6, 2006 Author Report Share Posted November 6, 2006 I swapped injectors with another cylinder. It didn't follow it. Dumb question, what is the firing order. Hope i am on the right cylinders...... Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted November 6, 2006 Report Share Posted November 6, 2006 1-8-7-2-6-5-4-3 is the firing order I believe. The drivers' side cylinders are 1-3-5-7 and the passenger side are 2-4-6-8 . Dave Quote Link to comment Share on other sites More sharing options...
SSThunder Posted November 7, 2006 Report Share Posted November 7, 2006 Help!!! I am stumped. I have a bad misfire on my 03 SS. I had a friend connect his handheld to it and we drove. It only does it on high rpm. Misfire on cylinder 6. I replaced the plug and coil. Still does it. The only mods i have are high flow mufflers and PCM4less tune. Any ideas where to go next? If it was an injector, wouldn't it do it all the time? HELP!!! <{POST_SNAPBACK}> Have you added LT or MT headers? I did and I'm also having trouble with misfires. Quote Link to comment Share on other sites More sharing options...
Bowtie70SS Posted November 7, 2006 Report Share Posted November 7, 2006 Another idea that has been mentioned before is that in a PCM4Less tune a lot of times the DTC for crankshaft position sensor relearn is disabled (no SES light). A miss at high RPM could be because you need a relearn done. Although I guess a code for random multiple misfire would be more likely if you needed a relearn. I didn't look to see where you are located but someone with HPT could do the relearn for you or the dealer will do it but it costs like $50. Good luck Dave Quote Link to comment Share on other sites More sharing options...
geowarr Posted November 10, 2006 Author Report Share Posted November 10, 2006 1-8-7-2-6-5-4-3 is the firing order I believe. The drivers' side cylinders are 1-3-5-7 and the passenger side are 2-4-6-8 . Dave <{POST_SNAPBACK}> Thanks for the info. I am on the right cylinder. I am out of ideas. Took it to the Chevy dealer today. Keep this up and i will have to get a new one. Quote Link to comment Share on other sites More sharing options...
.justin. Posted November 10, 2006 Report Share Posted November 10, 2006 Did you ever perform a crank relearn to rule that out? Quote Link to comment Share on other sites More sharing options...
geowarr Posted November 10, 2006 Author Report Share Posted November 10, 2006 Chevy dealer called today with good news and bad news. Bad news is it is my cats stopped up. Gonna have to replace them. Good news is they are still under warranty........ 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.