Please Help!
Thread Starter
Registered User
Joined: Jul 2002
Posts: 564
From: Palm Beach Gdns. Fl USA
Please Help!
Heres the story...
Car has 160K miles on it. Mostly stock minus a few bolt ons and PCMFORLESS tune. Car runs great, has great power, even gets pretty decent fuel mileage. A few things wore out, or broke recently, and I replaced them all (Starter, o2 sensors, battery etc...)
I have always had a problem after longer trips in the car (and then stopping at stop lights), or even with multiple short trips around town throughout the day, where I will be stopped at a light and my RPM's will just start going crazy. They will rise up to 1000 RPM and drop back down...then raise back up, and back down. It does this pretty much right after I come to a stop at the light, and wont stop until I begin to accelerate again.
There have been a few times where the RPM's would raise up, and then drop down, and the car even might lightly stumble real quick, but still keep running and not stall. This doesn't happen very frequently though, it usually just raises the RPM's and then drops, raises and drops etc...Almost like the car just wants to go by itself!
I did clean out the throttle body really well and got a ton of throttle response back from the car, and also cleaned out the IAC passage ways and even sprayed a little in my IAC cuz it seemed pretty dirty. Can anyone maybe shed some light on what may fix this problem because it really is annoying and needs to be fixed. Is my IAC staying closed, or even staying open? I really would not think this to be a fuel related issue as I do not have any other problems and the car doesnt do this when its just normal operating temperature or cold or anywhere in between. Please Help!
Cory
Car has 160K miles on it. Mostly stock minus a few bolt ons and PCMFORLESS tune. Car runs great, has great power, even gets pretty decent fuel mileage. A few things wore out, or broke recently, and I replaced them all (Starter, o2 sensors, battery etc...)
I have always had a problem after longer trips in the car (and then stopping at stop lights), or even with multiple short trips around town throughout the day, where I will be stopped at a light and my RPM's will just start going crazy. They will rise up to 1000 RPM and drop back down...then raise back up, and back down. It does this pretty much right after I come to a stop at the light, and wont stop until I begin to accelerate again.
There have been a few times where the RPM's would raise up, and then drop down, and the car even might lightly stumble real quick, but still keep running and not stall. This doesn't happen very frequently though, it usually just raises the RPM's and then drops, raises and drops etc...Almost like the car just wants to go by itself!
I did clean out the throttle body really well and got a ton of throttle response back from the car, and also cleaned out the IAC passage ways and even sprayed a little in my IAC cuz it seemed pretty dirty. Can anyone maybe shed some light on what may fix this problem because it really is annoying and needs to be fixed. Is my IAC staying closed, or even staying open? I really would not think this to be a fuel related issue as I do not have any other problems and the car doesnt do this when its just normal operating temperature or cold or anywhere in between. Please Help!
Cory
Guest
Joined: Sep 2004
Posts: 0
It sounds as though your IAC is stiff and doesn't move as smoothly as it once did causing it to take longer to find it's correct idle position.
In my p/up it would simply stay open longer at a light until it finally dropped down.
Replace it. Unless you haven't looked at the intake tubing from the air filter to the TB. In that case, check it first for tears or folds.
In my p/up it would simply stay open longer at a light until it finally dropped down.
Replace it. Unless you haven't looked at the intake tubing from the air filter to the TB. In that case, check it first for tears or folds.
Thread Starter
Registered User
Joined: Jul 2002
Posts: 564
From: Palm Beach Gdns. Fl USA
It sounds as though your IAC is stiff and doesn't move as smoothly as it once did causing it to take longer to find it's correct idle position.
In my p/up it would simply stay open longer at a light until it finally dropped down.
Replace it. Unless you haven't looked at the intake tubing from the air filter to the TB. In that case, check it first for tears or folds.
In my p/up it would simply stay open longer at a light until it finally dropped down.
Replace it. Unless you haven't looked at the intake tubing from the air filter to the TB. In that case, check it first for tears or folds.
Kind of stuck in a rut here, because I HATE replacing **** without knowing the true problem, and both the IAC and coil are two parts that are supposed to last a really long time and never go bad. Gotta figure out something, because it is REALLY annoying at a light and in traffic.
Cory
Guest
Joined: Sep 2004
Posts: 0
If you're referring to the ignition coil. I've never seen that account for surging. Especially while hot. They sometimes break down and begin to misfire when hot. They are considered a tune up item and should be replaced on a regular basis.
Looking at it may show the tell tale signs of misfiring by having little white spots on the side of the coil. Particularly near the laminations.
As far as the IAC is concerned, if the symptom shows up in the driveway you could try disconnecting it while it is idling well. See if the symptom goes away.
You could always scan it and see what the IAC counts are doing as well.
Looking at it may show the tell tale signs of misfiring by having little white spots on the side of the coil. Particularly near the laminations.
As far as the IAC is concerned, if the symptom shows up in the driveway you could try disconnecting it while it is idling well. See if the symptom goes away.
You could always scan it and see what the IAC counts are doing as well.
Registered User
Joined: Oct 2007
Posts: 1,174
When mine did that(surging)I was sitting at a taco bell drive thru,and I took it to my mechanic and he found a leak in those little hoses that run along side the intake manifold on the pass. side of the motor.I had to put it in neutral because the whole car was like power braking or something.Vacuum leak.Could be the intake manifold leak,mine was an easy check,#8 plug was all funked up with stuff,that was before the fix,later on.Hope this helps.(Even if the little tiny hoses look good the eye,might replace them,do the cheap stuff first).My02.