Still having crazy idle problems!
04-14-2009, 07:16 AM
#1
Thread Starter
Join Date: Sep 2008
Location: Ohio
Posts: 11
Still having crazy idle problems!
It's not the IAC valve, I've changed that like 3 times, and finally ended up unplugging it altogether and just driving it like that all winter. Just got new headers + oxygen sensors (it had none before), new h-pipe, all that crap put on this weekend... I figured maybe it had something to do w/ the oxygen sensors (or so I've been told it could), ... let it idle for quite some time yesterday w/ the IAC valve hooked back up and it seemed fine, drove it a short distance and it seemed ok, I thought for sure it was going to be good! Took off this morning and it started freaking out again, like just out of no where it will start idling super high, at least 3 to 4,000 rpms, just crazy.... and it won't stop... so I unplugged the damn IAC again and now it's running fine. Really wish I could figure this out! Any ideas??? Oh, it's a 90 GT 5.0...
04-14-2009, 12:23 PM
#2
1st Gear Member
Join Date: Aug 2008
Location: Ohio
Posts: 65
Mine does the same thing it doesnt idle up that high though it usually is at 800 rpms but somethimes when i get done driving it it will idle at 1500 rpms then i shut it off and it goes back to normal mines an 88 and ive been told its a common issue with them to have idling problems i went through and did a whole fuel flush injector flush and had my throttle body cleaned and it still does it i know its not much help but i know what your goin through maybe ill try the oxygen sensor.....
Last edited by 5.088lxdood87; 04-14-2009 at 12:24 PM. Reason: spelling
04-15-2009, 11:56 AM
#8
in limbo
Join Date: Jan 2007
Location: Iowa
Posts: 7,300
have you guys messed with anything lately or did this just start out of the blue?? usually the easiest and free way to verify something is wrong is pulling codes. this will tell if you if soemthing is out of adjustment or out of range.
if you dont want to do that you can also clean your MAF with the proper MAF cleaner, set your tps within proper range .6 to 1.01 volts with key on engine off, with car running base idle reset proceedures and verify base timing. those usually clear up some idle issues....but you should still pull codes.
if you dont want to do that you can also clean your MAF with the proper MAF cleaner, set your tps within proper range .6 to 1.01 volts with key on engine off, with car running base idle reset proceedures and verify base timing. those usually clear up some idle issues....but you should still pull codes.
04-15-2009, 12:36 PM
#9
Thread Starter
Join Date: Sep 2008
Location: Ohio
Posts: 11
FivePointOhh
Well, in my case, I have only had my mustang since last May, I bought it from a kid who obviously did a bunch of stupid stuff to it and that's a dead end trying to ask him what all he did, wires everywhere... it ran fine for the few few months, then all of a sudden started having the high idle problem... changed the IAC a couple times because people kept saying that had to be the problem, but it's not. I had long tube headers on, with no oxygen sensors, and just changed to short tube headers and put the oxygen sensors back on hoping that might help something... but I guess it didn't... I thought from the beginning it seemed like a vaccuum leak, but could never find one.
Weird thing is that it runs fine with the IAC unplugged, and everyone keeps telling me my car shouldn't idle worth crap with no oxygen sensors and the IAC unplugged, etc... but it runs fine! Still runs fine w/ it unplugged and the o2 sensors back on. I can hear that it wants to try to idle high at times, but it can't with that unplugged. This is my only problem (other than needing money for flowmaster mufflers, lol) and it's driving me batty, I mean the idle just freaks out...... haven't pulled codes yet, I may have a friend who has a code reader, I will check... kinda outta money at the moment so I can't bring it to the shop... I will let you know if getting the codes helps out at all... defintiely let me know if you have any other ideas, I want all the input I can get on this!! THANKS!!!
Weird thing is that it runs fine with the IAC unplugged, and everyone keeps telling me my car shouldn't idle worth crap with no oxygen sensors and the IAC unplugged, etc... but it runs fine! Still runs fine w/ it unplugged and the o2 sensors back on. I can hear that it wants to try to idle high at times, but it can't with that unplugged. This is my only problem (other than needing money for flowmaster mufflers, lol) and it's driving me batty, I mean the idle just freaks out...... haven't pulled codes yet, I may have a friend who has a code reader, I will check... kinda outta money at the moment so I can't bring it to the shop... I will let you know if getting the codes helps out at all... defintiely let me know if you have any other ideas, I want all the input I can get on this!! THANKS!!!
04-15-2009, 12:44 PM
#10
in limbo
Join Date: Jan 2007
Location: Iowa
Posts: 7,300
well lets see a picture of what the driver mod looks like 
well honestly considering the amount of things that may have been done incorrectly by previous owner i would start with pulling codes. you dont have to have a code reader to pull them. just a multi meter and a jumper wire....but it is a lot easier with a code reader. i have no idea of your mechanical ability but it is pretty simple to pull them with just the multi meter and jumper wire.
well honestly considering the amount of things that may have been done incorrectly by previous owner i would start with pulling codes. you dont have to have a code reader to pull them. just a multi meter and a jumper wire....but it is a lot easier with a code reader. i have no idea of your mechanical ability but it is pretty simple to pull them with just the multi meter and jumper wire.
Last edited by FivePointOhh; 04-16-2009 at 09:31 AM.