it will start idling normal a little below 1000rpm but will randomly jump up as high as 2000 and just stay there until i shut it off and restart it. then it will be good again as long as i drive like an old lady and dont rev up too high, but the second i go more than 1/4 throttle the rpms just hang way too high. the egr is unplugged with the vac line blocked, the iac as new, timing is good... i just ran a can of sea foam through it and it was better for like 10 minutes then started acting up again. im getting pretty frustrated now, not to mention i look like an asshole sitting at a red light revving up to 2000. any help or ideas would be appreciated. thanks Tim
check for vaccume leaks and make sure the throttle blade is clean and not getting hung up . It should open and close with no resistance . Look to make sure there is no air leaks between the air meter and throttle body . Other than that it could be a faulty TPS switch or a bad air meter .
if an EFI check the vacuum lines on the intake plenum. look for dry rotted hoses, hoses unplugged. theres also a vacuum line the run underneath the intake on the drivers side. just a suggestion of where to start lookin for leaks. good luck
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R.I.P. Specialist Matthew M. Pollini
....but it sure is fun
1992 Mustang GT-RIP GREEN HORNET