why does my 1999 gmc 1500 new body style and the engine is surging and when its warm and bring it to a idle it still surges.
Asked by ackerman56 Jan 10, 2016 at 11:07 AM about the 1999 GMC Sierra 1500
Question type: Maintenance & Repair
in the winter my pick up has been doing this for 5 years now. im finally trying
figure out what the problem is. when i first start it its really bad. my pick up
revs up to 5000 rpm then suddenly drops to 500. ive put in a new egr valve,
throttle positioning sensor and i replaced the plugs and wires. the only thing
that happened was it doesn't die anymore.
7 Answers
firebird338 answered 8 years ago
Did you try cleaning or replacing the ( IAC ) Idle Air Control ) valve or Mass Air Flow sensor depending on which one your vehicle has.
ackerman56 answered 8 years ago
it runs fine when im driving. its just when i slow down to a stop and it idles like shit.
my 2005 Vortec 5.3 did the same thing and I researched it on youtube your truck sounds a lot older than mine but I went and bought a can of mass air flow sensor cleaner, and very carefully removed the fine screen with an electrical connector that connects to it and sprayed it through let it dry sprayed it again several times, and then very carefully reassemble it and it did take care of the problem. I hope this will help you if not try YouTube there is a lot of information on there, best of luck:-):-)
Mine does the same thing I have replaced almost all sensors and still doing it.
