RacerJJ Posted April 18, 2008 Report Share Posted April 18, 2008 My brother has a 2000 Sierra 5.3. It has about 120k on it. He has been reporting that it seems to be missing or sputtering a bit at idle and at accelertation. There is no SES light present and we have changed the plugs, PCV valve, fuel filter, and have done a Se Foam treatment in the gas with no results. Could it be a bad cat? Clogged injectors? Any help would be appreciated. I am going to scan it tonight to see what it's doing but until then, any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
chpspecial Posted April 18, 2008 Report Share Posted April 18, 2008 if you are going to use hptuners, do an cylinder balance test... also make sure that you didn't crack a spark plug while changing them Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 18, 2008 Author Report Share Posted April 18, 2008 if you are going to use hptuners, do an cylinder balance test... also make sure that you didn't crack a spark plug while changing them Thanks, will do. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 18, 2008 Report Share Posted April 18, 2008 Just last weekend I replaced my stock plug wires with MSDs (they had 60K on them) and it fixed an off-idle hesitation and minor rough idle. FWIW. Mr. P. Quote Link to comment Share on other sites More sharing options...
eddieo818 Posted April 18, 2008 Report Share Posted April 18, 2008 im thinking maybe the cats... Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 18, 2008 Author Report Share Posted April 18, 2008 im thinking maybe the cats... So was I. We tried my old MSD wires on it and that didn't help. Quote Link to comment Share on other sites More sharing options...
SSThunder Posted April 18, 2008 Report Share Posted April 18, 2008 what about a bad fuel pump or o2? Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 18, 2008 Author Report Share Posted April 18, 2008 what about a bad fuel pump or o2? Fuel pump may be a good idea to try. I would think the o2 would throw a code. It did on mine when it went south a couple of months ago. Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 18, 2008 Author Report Share Posted April 18, 2008 According to him, the truck runs okay once it is past 2000 rpm or so. At that point, it only stutters a bit when he stabs the throttle to pass someone or something, Quote Link to comment Share on other sites More sharing options...
12'SROCK Posted April 18, 2008 Report Share Posted April 18, 2008 According to him, the truck runs okay once it is past 2000 rpm or so. At that point, it only stutters a bit when he stabs the throttle to pass someone or something, have you cleaned the MAF yet? that should help some Quote Link to comment Share on other sites More sharing options...
brobradh77 Posted April 18, 2008 Report Share Posted April 18, 2008 Is this a new problem or an exsisting one? Quote Link to comment Share on other sites More sharing options...
RacerJJ Posted April 18, 2008 Author Report Share Posted April 18, 2008 Art: Yes, cleaned the MAF and nothing. Brad: It was a little hesitant before the plug change and has progressively gotten worse. The overall "problem" has been progressively getting worse for a couple of months now. Quote Link to comment Share on other sites More sharing options...
12'SROCK Posted April 18, 2008 Report Share Posted April 18, 2008 last thing i can think of is a weak coil or bad plug wires Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted April 18, 2008 Report Share Posted April 18, 2008 I would do a fuel pressure test for sure. Also, try cleaning the throttle body & IAC Valve really good if u haven't already. Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted April 21, 2008 Report Share Posted April 21, 2008 bad injector? Quote Link to comment Share on other sites More sharing options...
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