95 gt will not idle

[383blaze]

been tryin to figure this one out for about a month,,the car starts and runs fine,but just as soon as you touch the gas as if just to rev it,,,and it goes back to idle the rpms jump to 1800 and the back to 500 or less and it does this until it dies,,havent replaced any sensors yet,,it isnt setting off any codes as far as i can tell,,it set off the engine light one time with me driving and it just totally lost power,then as soon as it started it stopped and car went back to the way it was,,any ideas,,,MAF maybe,,,idle control maybe,,,hmm,,it just started doing this after i put new battery on btw,already cleaned the maf with injector cleaner,,looked very clean before anyway.

and one more thing,,this is an AOD car,,has one of you guys ever put a clutch in one of these ,,difficult?

 

[R.J.]

Try resetting your idle with the following procedure. If your idle problem is NOT being caused by a bad part then I have never seen this not fix the problem!

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC.

Now remember we adjusted the set screw on the throttle body. That means that the voltage reading from the TPS sensor has changed. It should read between .96 and .99 volts. Anything outside of that range will cause all sorts of issues including misfires and rough idle.

you will have to back probe the TPS connector. With the connector attached to the TPS stick a paper clip into the rubber boot on the connector where the top and middle wires go into the connector. The rubber is very flexible the paper clip will slide in between the rubber and the wire.

Set your multimeter to volts. Turn ignition to ON. Then place your multimeter leads on the metal pins. If it comes up as a negative that is okay as long as you are -.96 to -.99. If you get this reading then great you are done and hopefully your issues are gone. If not proceed to step 9

This is where and extra pair of hands come in handy. Using a large screw driver you will need to loosen the bolts that hold the TPS. DO NOT USE A SCREWDRIVER THAT IS TOO SMALL BECAUSE YOU WILL STRIP THE BOLTS. They probably will be really tight so you have to really lean on the screwdriver and use some finesse.

Once the bolts are loose you will need to move the TPS up or down and continue to read the voltage. Once you get it to the desired setting you can retighten the bolts. What I do is I find .97 and then as carefully as possible I tighten the TPS down. what will happen is the voltage will change usually to .96 or .98 but that it okay. Once you are done with this manually open the throttle body a few times and close it then reread the voltage and make sure it is still within our desired range.

Depending upon how loose your set screw was you might want to cover it in RTV to hold your setting. At this point you have CORRECTLY reset you idle.

 

[HISSIN50]

A vac leak can cause such issues as yours.

 

[hollywoodstang]

Replace your IAC. that's it

 

[Zero_chance]

Though the IAC can be the cause of some idle problems, statements like that generally arent very helpful because what if thats not it and he just went out and wasted X amount of dollars on a new IAC and it still does the same thing? No return on electrical parts. Id try the idle reset procedure. If you search around theres another good writeup about it with pictures and details on how to clean your MAF sensor if youre so inclined. Theres also specialty MAF sensor cleaner you can buy at parts stores.

 

[Chythar]

While the idle adjustment above works just fine for us, it's my understanding the TPS on the 94-95 5.0 engines doesn't need adjustment. The computer reads the value at startup \9.93, 1.04, etc) and treats that value as if it was 1v. It adjusts it readings accordingly.

 

[mustang6tee8]

and one more thing,,this is an AOD car,,has one of
you guys ever put a clutch in one of these ,,difficult?

Do you mean a torque converter?

 

[BlackVert]

what is the rest of the engine combination? what intake, heads, cam are on it?

AODs don't have clutches

 

[383blaze]

what is the rest of the engine combination? what intake, heads, cam are on it?

AODs don't have clutches

bone stock 95 gt 5.0 ,,,,,,,,,,,,,,,,,,thats the question,,how difficult is it to install a clutch in an auto car,,anyone here ever done it,,,i hate auto mustangs,but wife gets new car in july,,i get the stang,going to try the reset this morning,,ill let you guys know,,but this is probably not a maf sensor right,,no backfire,that kinda stuff,,im thinking tps,,but well see,,gonna try reset first

 

[383blaze]

Replace your IAC. that's it

any likely spots for a leak?

 

[383blaze]

Do you mean a torque converter?

a clutch,,it is an auto car,,want 5 speed.

 

[383blaze]

While the idle adjustment above works just fine for us, it's my understanding the TPS on the 94-95 5.0 engines doesn't need adjustment. The computer reads the value at startup \9.93, 1.04, etc) and treats that value as if it was 1v. It adjusts it readings accordingly.

if that is true,TPS should be my issue,,like i said,it started gradually,every once in a while,,i changed battery and it does it all the time now

 

[383blaze]

i really think its a bad part because of the idle surge.but im no expert,

 

[hollywoodstang]

I have both the TPS and IAC. TPS came with FMS throttle body as well as IAC. let me know if you want them.

 

[tim_lemmy]

A vac leak can cause such issues as yours.

+1 from experience w/ my firebird

 

[383blaze]

Replace your IAC. that's it

good call,,that was it,,thanks

 

[383blaze]

any of you fellas got a cold air for this car,,want to get rid of it,,email me. [email protected]