TLDR: Replaced IAC and cleaned throttle body and MAF to stop erratic idle, and it worked for a little while, but two days later my throttle is getting stuck closed, car is shifting into 3rd at around 30mph and doesn't downshift until I come to a complete stop, causing the car to stall out. Help is appreciated, more details are below.
Okay, so, I've spent almost all my free time over the past week trying to chase down an idling problem with 2002 GT. Over the last few months, I've been having intermittent problems with intake grumbling and RPMs bouncing around below 1k. I cleaned the throttle body, MAF, IAC, got a new air filter, and turned my idle up with the throttle adjustment screw, and it fixed the problem... for one day.
Next day, hesitation and idle got worse, so I said "screw it" and bought a new IAC. First time I started the car up, it immediately shot up to 2krpm in park, and stayed there for a solid 2 seconds, before dropping down to regular cold start rpm. Weird, but I figured the computer was adjusting to the new part. I reset the computer beforehand, btw.
I took it for a drive after that, and it completely fixed my problem. But once again, only for the night.
Next day, whenever you'd rev the car up, it would hang there for a second or two, before coming back down to idle. I read that turning the throttle adjustment up could cause this, so this morning, I went outside and tried to turn it back down to factory spec. I marked where it was with a sharpie before I ever messed with it.
Now, here's the weird part. When I went out there to do that, I noticed a lot of resistance on the throttle linkage. It wasn't doing that yesterday. When I loosened the throttle body adjuster, the linkage didn't move from its spot. Even putting a little force on it couldn't make it move down from what I set my idle to before. Starting the car didn't do anything. I put the screw back to where it was and figured I'd fix it later, since I had to get to school.
I take my car out to drive to school, and notice that it's shifting into second and third WAY sooner than it should. I'm talking 3rd gear at 30mph. It also didn't want to shift down until you came to a complete stop, which would cause the car to stall at every light. After the second stall I put on my flashers and limped it home.
I'm at a loss here. Any suggestions for what to do are appreciated. Thanks.
EDIT: Tried the starter fluid trick to check for vacuum leaks. Found nothing. Going up to O'Reilly's later on today to exchange the IAC. It's a Borg Warner, if anyone is wondering.
Okay, so, I've spent almost all my free time over the past week trying to chase down an idling problem with 2002 GT. Over the last few months, I've been having intermittent problems with intake grumbling and RPMs bouncing around below 1k. I cleaned the throttle body, MAF, IAC, got a new air filter, and turned my idle up with the throttle adjustment screw, and it fixed the problem... for one day.
Next day, hesitation and idle got worse, so I said "screw it" and bought a new IAC. First time I started the car up, it immediately shot up to 2krpm in park, and stayed there for a solid 2 seconds, before dropping down to regular cold start rpm. Weird, but I figured the computer was adjusting to the new part. I reset the computer beforehand, btw.
I took it for a drive after that, and it completely fixed my problem. But once again, only for the night.
Next day, whenever you'd rev the car up, it would hang there for a second or two, before coming back down to idle. I read that turning the throttle adjustment up could cause this, so this morning, I went outside and tried to turn it back down to factory spec. I marked where it was with a sharpie before I ever messed with it.
Now, here's the weird part. When I went out there to do that, I noticed a lot of resistance on the throttle linkage. It wasn't doing that yesterday. When I loosened the throttle body adjuster, the linkage didn't move from its spot. Even putting a little force on it couldn't make it move down from what I set my idle to before. Starting the car didn't do anything. I put the screw back to where it was and figured I'd fix it later, since I had to get to school.
I take my car out to drive to school, and notice that it's shifting into second and third WAY sooner than it should. I'm talking 3rd gear at 30mph. It also didn't want to shift down until you came to a complete stop, which would cause the car to stall at every light. After the second stall I put on my flashers and limped it home.
I'm at a loss here. Any suggestions for what to do are appreciated. Thanks.
EDIT: Tried the starter fluid trick to check for vacuum leaks. Found nothing. Going up to O'Reilly's later on today to exchange the IAC. It's a Borg Warner, if anyone is wondering.