Denunzio36

No vacuum leak, idle still comes down very slow in between shifts. I have replaced my IAC. Does anyone know what my problem is? Could it be the VSS? Computer problem? I have tried all that I can think of. This car has 24lb injectors, Trick Flow intake, adjustable fuel pressure regulator, MSD ingnition. Could any of this be creating this problem? Please help

IownaMustangNow

ell me your car for like 2 or 3 grand
and ill fix it up and let u know what i found to be the problem

birdman076

My hanging idle problem on my 91 was the ACT sensor. Might want to give that a try, mine was all gummed up so for $12 I replaced it rather than clean it.

philly3384

I have the same damn problem i changed the iac and the tps and looks for leaks and nothing the only time it stops is when i disconnect the wire to the tps. When thats unplugged it drops in idle but runs for **** cuz its not sending the right mixture. So whats teh deal... unplug urs and see if it does the same thing.

91hatchgt

Mine used to do that.. I adjusted the TPS and it fixed it a little, then when i got a new TB, it fixed it completely

roundman

clean inside the throttle body with some good carb cleaner to remove all the carbon deposits left there by the EGR valve as they may be hanging up the throttle some when you let off the gas pedal.

Denunzio36

I am going to replace both upper and lower intake manifold gaskets to make sure that it is not a vacuum leak. While I'm in there I am going to clean out the Throttle body (Less than 10k miles on it). I hope it works; if not, I'll be back.


Philly3384- Do you think that it could be a bad TPS? If it worked fine when you unplugged, wouldn't that mean that is wasn't working right to begin with? Let me know. Thanks for the feedback guys

stanglx2002

it sounds like it is bad and i would change it. Have you run the codes on the car?

Denunzio36

Ok, here's the verdict. I unplugged teh TPS Sensor and teh RPM's came down fast. Much faster than they should. But the down side of unplugging the TPS is that there is zero throtle response. So what is the problem? If I get a new TPS will the RPM's still come down slow? Do the parameters in the computer need to be adjusted?.....or can I even do that? Your input is good stuff guys. Thanks


Stanglx2002: I have run the codes in the car and they come up as EGR. I have changed that out since, so now I think it's throwing wrong codes. I'm thinking I should run them again. Thanks

philly3384

Hey i unplugged it too and i automatically thought.. HEY thats the problem so i went and bought a new one!!!!! and guess what that wasnt it lol its something else .. i also changed out the IAC and that wasnt it either!!!!! after awhile it does start to irratate me hopefully someone can come up with a solution lol..