Idle issue 98 Cobra - Sometimes when i drive my car and stop at a stoplight my car will idle at 1200 rpm instaed of 800 the only way to get it back to 800 is to cut the car off and restart it. Bolt ons include Basani x pipe with cats, magnaflow catback, under drive pullies, frp coilpacks, 3:73 gears,aluminum driveshaft and SCT programmer. It has 56k miles.
Idle issue 98 Cobra
- Thread starter imports suck
- Start date
Maybe your IAC is dirty?:shrug:
yeah try cleaning your IAC, you can use carb cleaner for that, i just cleaned my a few days ago and seemed like it idle'd better.
imports suck said:
The problem is not your IAC. This is a symptom of a bad TPS. I just went through the same problem on my Fox. Replace your Throttle Position Sensor and make sure you verify correct TPS voltage after installation.
How to find out IF it is the IAC:
Start up the car, remove the 2 IAC screws. Place open palm on the IAC opening. Putting your hand on the IAC cover should make the car stay alive and not shut down. The car should want to stall when you take the IAC off, and when you cover it with the palm of your hand, the idle should come to almost normal. (You can have a friend start up the car, or if you have no help, while you take the IAC screws off, you can keep the motor alive by pulling on the throttle cable until you take the screws off and can cover the empty hole by your hand)
This is what the test should aim to prove:
1. With IAC on, the car idles high
2. With IAC removed and hole covered by hand, idle should be almost normal
..which should conclude that the IAC is indeed bad and needs to be replaced.
(If the idle is still high while your palm has the opening covered, then the problem lies elsewhere)
Start up the car, remove the 2 IAC screws. Place open palm on the IAC opening. Putting your hand on the IAC cover should make the car stay alive and not shut down. The car should want to stall when you take the IAC off, and when you cover it with the palm of your hand, the idle should come to almost normal. (You can have a friend start up the car, or if you have no help, while you take the IAC screws off, you can keep the motor alive by pulling on the throttle cable until you take the screws off and can cover the empty hole by your hand)
This is what the test should aim to prove:
1. With IAC on, the car idles high
2. With IAC removed and hole covered by hand, idle should be almost normal
..which should conclude that the IAC is indeed bad and needs to be replaced.
(If the idle is still high while your palm has the opening covered, then the problem lies elsewhere)
.97 to .98 volts should be read at idle, get a multimeter and try it,
i did my bbk 65mm TB and had to do this it is now fixed. u have to adjust the screw to get the volts where u nedd them to be, by the way did this problem just happen all of a sudden or gradually? if it happened all of a sudden get a new TPS just to be safe otherwise check your voltage.
i did my bbk 65mm TB and had to do this it is now fixed. u have to adjust the screw to get the volts where u nedd them to be, by the way did this problem just happen all of a sudden or gradually? if it happened all of a sudden get a new TPS just to be safe otherwise check your voltage.
Ok, I have the same idle issues in my 98, except mine is at 1600RPMs.
I cleaned the IAC and it did nothing.
I replaced the IAC and it fixed it for about 2 weeks, then the problem came back again.
I replaced my TPS and it did nothing either.
I'm wondering if the IMRCs could be sticking open slighty and not closing after dropping below the 3250.
I cleaned the IAC and it did nothing.
I replaced the IAC and it fixed it for about 2 weeks, then the problem came back again.
I replaced my TPS and it did nothing either.
I'm wondering if the IMRCs could be sticking open slighty and not closing after dropping below the 3250.
Make sure TPS is set to .97-.98
badass98svt said:
Did you reset your ECU after doing all of these things? When the idle climbs up and doesn't go back down, it's a symptom of a bad TPS. Try replacing the TPS and reset the ECU.
Did you read what you quoted?
Im DID replace the TPS.
As soon as the rain stops, I'll be attempting to set the TPS to .97-.98
I bought a multimeter yesterday, but it's been pouring out ever since!
Im DID replace the TPS.
As soon as the rain stops, I'll be attempting to set the TPS to .97-.98
I bought a multimeter yesterday, but it's been pouring out ever since!
50 Proof said:
Did you read what I said? Reset your damn ECU after you replace computer controlled parts!!! Sorry, just don't appreciate getting an attitude from people when all I'm trying to do is help.
In addition to setting your TPS voltage to .98. You have make sure voltage steadily increases and decreases as you open and close the throttle.
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Yes, I read what you said. Of course I reset the ECU.
If I didn't i would've said so after reading your post.
I wasn't trying to give you an attitude, just wanted to make sure you read my post. It's hard to pick up on a person's "tone" when all we do is read peoples typing. Sorry for any confusion.
If I didn't i would've said so after reading your post.
I wasn't trying to give you an attitude, just wanted to make sure you read my post. It's hard to pick up on a person's "tone" when all we do is read peoples typing. Sorry for any confusion.
Replaced TPS and cleaned IAC so far so good thanks guys for your help!
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