bowling green Posted January 12, 2016 Share Posted January 12, 2016 My 2000 corvette has a hesitation at about 2500 rpm it stumbles then picks up until a little over 3000 stumbles some more then almost feels like a rev limiter at about 4000 rpm. I have changed the fuel filter and just did the ls1 to ls3 mod for the pcv valve, thinking that it had a vacuum leak. no help with either of those. Any suggestions? Link to comment Share on other sites More sharing options...
Grape Ape Posted January 12, 2016 Share Posted January 12, 2016 Good to see you hear FINALLY...Someone should be able to help you here. Link to comment Share on other sites More sharing options...
JohnU Posted January 12, 2016 Share Posted January 12, 2016 I used to do a "Seafoam cocktail" in my father's 450SL w/clogged injection. 2 cans of Seafoam + 1 can of Techron (black bottle)..... one trip down the highway at WOT and in a few miles all was well for another 6 months. Link to comment Share on other sites More sharing options...
Ted Y Posted January 12, 2016 Share Posted January 12, 2016 Have you ever changed the spark plugs? Link to comment Share on other sites More sharing options...
bowling green Posted January 12, 2016 Author Share Posted January 12, 2016 I have not yet. I will today 12 hours ago, JohnU said: I used to do a "Seafoam cocktail" in my father's 450SL w/clogged injection. 2 cans of Seafoam + 1 can of Techron (black bottle)..... one trip down the highway at WOT and in a few miles all was well for another 6 months. I will try this today also Link to comment Share on other sites More sharing options...
Unreal Posted January 12, 2016 Share Posted January 12, 2016 Before touching the seafoam, plugs/wires should be replaced. Link to comment Share on other sites More sharing options...
bowling green Posted January 12, 2016 Author Share Posted January 12, 2016 I replaced the plugs and wires today it is definitely running better. The hesitation does not happen every time now. But it is still happening, approximately three times in a 5 mile ride. Seems like a sensor or vacuum or something that's causing it at 2500 RPM every time??? Link to comment Share on other sites More sharing options...
Unreal Posted January 13, 2016 Share Posted January 13, 2016 What plugs and what did you gap them too? No CE lights? Link to comment Share on other sites More sharing options...
bowling green Posted January 13, 2016 Author Share Posted January 13, 2016 I used Bosch platinum plugs and gaped them to .60 nit sure what ce lights are. But I have no codes on any computer Link to comment Share on other sites More sharing options...
Ted Y Posted January 13, 2016 Share Posted January 13, 2016 check engine lights Does it have the factory tune or a custom engine tune? Link to comment Share on other sites More sharing options...
bowling green Posted January 13, 2016 Author Share Posted January 13, 2016 As far as I know. It's a factory tune. I have only owned the car for about 7 months. Shortly after I bought it I got a check engine light and code for secondary air pump so I had it programmed out and the fans set to 190 degrees. But that's all. Link to comment Share on other sites More sharing options...
Ted Y Posted January 13, 2016 Share Posted January 13, 2016 Read this. Also post up your code you were getting. My money is on a vacuum leak at this moment. It's probably not a good idea in the future to tune out a check engine light instead of fixing the problem causing it. http://www.corvetteforum.com/forums/c5-tech/629845-secondary-air-injection-system-problem.html Link to comment Share on other sites More sharing options...
joe@cpr.com Posted January 13, 2016 Share Posted January 13, 2016 with the car running spray brake cleaner around the air intake, maf sensor, and intake manifold. We have had 2 C5's in the past 3 months come in w/ cracked housings on the Maf causing issues. If you had a scanner you could watch the fuel trims and see which side it's on and a few other things. Post up some more stuff and I will try and help you out on here. Link to comment Share on other sites More sharing options...
Unreal Posted January 13, 2016 Share Posted January 13, 2016 Platniums are ugh, and .060" is pretty huge on the gap. Not sure why you did plats or .060". I would replace those with some quality copper plugs and gap them down. Link to comment Share on other sites More sharing options...
bowling green Posted January 13, 2016 Author Share Posted January 13, 2016 I used platinum because they are what the guy at oreilly said were original and the gap I got from the owners manual Link to comment Share on other sites More sharing options...
bowling green Posted January 13, 2016 Author Share Posted January 13, 2016 Ok Joe I will try the brake cleaner today Link to comment Share on other sites More sharing options...
Two Fangs Posted January 17, 2016 Share Posted January 17, 2016 There is a TSB on that spark plug gap, it is listed as spec incorrectly. It should be dropped down to .040" Platinum and iridium plugs should not be gapped, so I would recommend picking up a set of AC Delco 41-962 plugs preset at the factory gap and see if that cures your problems. My bet is that it will. All the best~ The guy that doesn't know anything Link to comment Share on other sites More sharing options...
Unreal Posted January 18, 2016 Share Posted January 18, 2016 100% agreed with Two Fangs. Lesson learned, never trust an autoparts store guy, EVER. In fact I would be really weary to even listen to a dealer person. Most of them have no clue. Link to comment Share on other sites More sharing options...
bowling green Posted January 18, 2016 Author Share Posted January 18, 2016 I will change the plugs again next weekend and let you all know if it fixes my problem. Thanks for all the help Link to comment Share on other sites More sharing options...
F22trainer Posted January 29, 2016 Share Posted January 29, 2016 Well, any new developments? Link to comment Share on other sites More sharing options...
bowling green Posted January 29, 2016 Author Share Posted January 29, 2016 No I spent last weekend fixing my truck. But my car it running worse. It just completely falls on its face at about 3500 rpm. It won't go past about 3700. To 3800. I am planning on trying the new plugs this weekend. A friend said he uses ngk tr55 on his c5. Any thoughts on those? Link to comment Share on other sites More sharing options...
Bigfoot Posted January 29, 2016 Share Posted January 29, 2016 They'll be good. Link to comment Share on other sites More sharing options...
TheCMSH Posted January 29, 2016 Share Posted January 29, 2016 Make sure your wires are seated tightly. Easy enough to miss. You could've cracked an insulator on one of the new plugs too Link to comment Share on other sites More sharing options...
bowling green Posted February 2, 2016 Author Share Posted February 2, 2016 So I changed the plugs out today and it ran better but still hesitated around 2500. So I took of the maf and removed the screen and cleaned the elements with a q tip and alcohol now it runs like new. Thanks to everyone for the help Link to comment Share on other sites More sharing options...
Azmotorhead Posted February 6, 2016 Share Posted February 6, 2016 Good to hear you got it ironed out. Hmmm.... who gave you the tip on cleaning the MAF?? Link to comment Share on other sites More sharing options...
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