Revving up between shifts

hips95gt · Apr 19, 2007

:help2: I have noticed that my 95 Gt will rev up between shifts (It is a 5 speed) when I let off the gas and push in the clutch. I just put on my headers , off road h pipe and , my 2 chamber Flowmaster exhaust. I never noticed it before changing the exhaust but it is way louder now so it might have been doing it all along. I also removed the smog pump and capped off the vacuum lines that went to the smog diverter valve. Is this normal for this year ?? I also have an 86 Gt with a 87 drivetrain in it but it doesn't rev up between shifts like my 95 does .. I need to know if I have a problem or not. I also put on a CAI with the filter in the fender well and I checked for leaks around the Mass Air Meter but that is OK Thanks for any help !!! :help2:

Trickflow.GT · Apr 19, 2007

clean out your IAC and check Tps voltage..

ryclef331 · Apr 19, 2007

If you're rolling along and just depress the clutch, does the car STAY revved up? If yes, Hold the clutch in and come to a complete stop...does the car stay revved up until you come to a complete stop? If yes, check the TPS voltage its probably messed up.

Downshift · Apr 19, 2007

I think I have/had the same problem.

You are just driving along and when you shift (Clutch in/No gas) Instead of RPMs going down they rev a couple hundred RPMs? Like say you shift at 3000 they go up to 3200-3300 before they start to go down right?

I had the same problem. Never figured it out. My TPS was reading 1.02 though so that might have been the problem. I dont know if it is doing it now though I just swapped in a 93 cobra intake a 70mm fox style TB which has the fox TPS so I will have to see.

ryclef331 · Apr 19, 2007

It could be either A) the TPS is messed up causing a crappy signal to the IAC and allowing it to open too much as well as not dropping the timing back down or B) the IAC sticking open too much...clean the IAC with some brake or carb cleaner (you have to take it off to do so)

trav_19 · Apr 22, 2007

i think im reading it wrong but it sounds like you have a slipping clutch

94 Bullitt · May 12, 2007

I'm having the same problem! I just took off my IAC and the holes in the TB where clean, but your saying cleen out the IAC its self?

ripper · May 12, 2007

Yea thats what he means. Spray it down real good with carb cleaner.

94 Bullitt · May 14, 2007

So I srayed it down good and reassembled, it still ran the same! I drove it for awhile thinking the ecu neededto learn. when I got home I poped the hood and saw I forgot to plug in the M.A.F., I pluged it in and took off, ran the same. I pulled over pluged it in and took off, ran the same. Could this be a faulty M.A.F. ?

trav_19 · May 14, 2007

94 Bullitt said:
So I srayed it down good and reassembled, it still ran the same! I drove it for awhile thinking the ecu neededto learn. when I got home I poped the hood and saw I forgot to plug in the M.A.F., I pluged it in and took off, ran the same. I pulled over pluged it in and took off, ran the same. Could this be a faulty M.A.F. ?

...you could drive it with the maf being unpluged?!?!? mine would barely idle when i had it tore apart doing my work this winter and needed to let it run for a sec.. i dont know how it could possibly be driven that way ...i thought the engine was trying to leap out of the bay...

94 Bullitt · May 15, 2007

Yeah it drove just as I described above. :help2: I don't wanna waste money just replacing parts. any body else have this problem?

skielk · May 15, 2007

Something isn't right there with out a MAF sensor your car shouldn't run well enough to move under its own power, even just causing a small leak after the MAF sensor will cause the car to stumble pretty bad. I can't tell you what is wrong but if you car is able to be driven without the MAF sensor being hooked up I would start there.

91paxmustang · May 15, 2007

When my MAF sensor went bad in my 89 GT when i would increase the rpms it would break up and not run for crap. it ran really good with the maf connector disconnected, but it ran a little to lean. I replaced and it was fine afterwards. so it doesnt sound like the maf.

94 Bullitt · May 15, 2007

How can I test my IAC?

joef · May 16, 2007

You have to take the IAC off and hook up a 6 volt battery to the iac with leads. Look inside and you will see a rod that should move very little when you apply the power from the battery. If you have a autozone or parts store in your area they can check them for free.

SVTGizzi · May 16, 2007

i have the same problem with mine, with basically the same mods...and i know it has done it since the car was stock. i cleaned the IAC, throttle body, and mass air a week ago. even though the car runs MUCH better, the r's still go up 100-200 and hang just for a second before they come back down when i engage the clutch. it doesnt really bother me, so i havn't worried much about it...

94 Bullitt · May 16, 2007

So today I unpluged the IAC and took a drive and the RPM's fell fast but ran and drove fine with the idol at 900-1000 RPM. now I pluged in the IAC and the idol won't fall below 1100 RPM and it revvs inbetween shifts. Im gonna take it to Autozone tomorrow and see what they think but I think I need a new one.

Downshift · May 16, 2007

94 Bullitt said:
So today I unpluged the IAC and took a drive and the RPM's fell fast but ran and drove fine with the idol at 900-1000 RPM. now I pluged in the IAC and the idol won't fall below 1100 RPM and it revvs inbetween shifts. Im gonna take it to Autozone tomorrow and see what they think but I think I need a new one.

Mine is still doing it after changing to a cobra intake and 70mm throttle body. The TPS is at .90 and its a fox body sensor and TB. Cant get it to be any higher then that. I unpluged my IAC and it ran alright but if I had my heater and lights on the volts would tweak out pretty bad. This rev inbetween shifts is pissing me off so damn bad haha. It sounds like I am giving it gas while I push the clutch in and makes me look like a shitty driver haha. Sometimes it doesnt do it and its all good but most of the time its like 300 rpms..... Im not sure what else to look at I need to figure out my tps first though how do I get it past .90