Idle surging?
Thread Starter
Racer
Joined: Apr 2014
Posts: 408
Likes: 491
From: Grand Forks ND
2024 C5 of the Year Finalist - Modified
2023 C5 of the Year Finalist - Modified
Idle surging?
I have a 2000 Corvette with 112000 miles on it. Only mods I have on it are longtubes and a blackwing. Yesterday I started the car and it idled at 1100 til it warmed up then it started to jump from 400 to 1100. It did that a couple of times and then it died. I tried to take it for a little drive. When I was driving it was running smooth for a while, but then it felt like it cut out followed shortly by a backfire. Any ideas?
Race Director
Joined: Jul 2007
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From: Reno is so close to Hell you can see Sparks , State Of Confusion
St. Jude Donor '12-'13-'14
Thread Starter
Racer
Joined: Apr 2014
Posts: 408
Likes: 491
From: Grand Forks ND
2024 C5 of the Year Finalist - Modified
2023 C5 of the Year Finalist - Modified
those have been on for a while as I dont have rear O2s and I havent had a tune yet since the headers.
Wondering if it might be a vacuum leak.
Wondering if it might be a vacuum leak.
Burning Brakes
Joined: Dec 2003
Posts: 1,243
Likes: 5
From: Loveland CO
sounds like a vac leak. If the idle is hunting when cold then warms up your intake seals might be leaking, (metal heats up and xpands then seals the leak) try spraying some carb/brake cleaner around where the heads and intake meet. our cars use the Throttle body to control idle air rather then a IAC valve so no problem there. but could be a bad primary sensor not heating up and reading accurately. I would think a intake leak would give a lean code as well but maybe not.
Any way to scan the car? so that you can see the MAF and O2 sensor activity? try unhooking the maf and see if that smooths out the idle.. could be dirty or bad maf..
Any way to scan the car? so that you can see the MAF and O2 sensor activity? try unhooking the maf and see if that smooths out the idle.. could be dirty or bad maf..
Last edited by RedZMonte; Nov 3, 2014 at 01:24 PM.
Racer
Joined: Oct 2011
Posts: 372
Likes: 2
From: Richmond BC
sounds like a vac leak. If the idle is hunting when cold then warms up your intake seals might be leaking, (metal heats up and xpands then seals the leak) try spraying some carb/brake cleaner around where the heads and intake meet. our cars use the Throttle body to control idle air rather then a IAC valve so no problem there. but could be a bad primary sensor not heating up and reading accurately. I would think a intake leak would give a lean code as well but maybe not.
Any way to scan the car? so that you can see the MAF and O2 sensor activity? try unhooking the maf and see if that smooths out the idle.. could be dirty or bad maf..
Any way to scan the car? so that you can see the MAF and O2 sensor activity? try unhooking the maf and see if that smooths out the idle.. could be dirty or bad maf..
Just connect a 3 or 4 ft tube to a propane nozzle to direct it where you suspect a leak. you will hear the idle increase when you hit the leak with a stream of propane.
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