Bad Stumble... WTF ???

[StangLou]

Which screw are you talking about? If you know which one is the actual throttle adjust screw on a stock tb... PLEASE POST A PIC OF IT lol. I dont want to take it into my shop and be like duhhhh I cant find the throttle adjust screw lol can you increase my idle .

 

[00VERT GT]

there is no screw on the stock tb. i've over that damn thing 100x couldn't find s***.

 

[pduffy02]

I am having the same problem in my 98 GT, RPM drops while driving and at idle. My car dies sometimes and has now gotten extremely bad where I can't control it with flooring the pedal anymore. The engine light came on and now the car dies while driving. I had a diagnostic done and the mechanic says its throwing a bunch of codes. He can't figure out the problem. What the hell is the problem!

 

[JonJon]

there is no screw on the stock tb. i've over that damn thing 100x couldn't find s***.

damn stockers... how do you control the idle level then?
Guess you don't?

I am having the same problem in my 98 GT, RPM drops while driving and at idle. My car dies sometimes and has now gotten extremely bad where I can't control it with flooring the pedal anymore. The engine light came on and now the car dies while driving. I had a diagnostic done and the mechanic says its throwing a bunch of codes. He can't figure out the problem. What the hell is the problem!

Get him to give you a list of the codes and make a new thread here with those codes, your mods, and the problems.

AutoZone can pull the codes and print them for you for free.

 

[pduffy02]

I'll try to get the codes from him a little later but in the meantime these are the mods:

1998 Mustang 5 spd GT, 36,000 orig miles
flowmaster cat back
screamin demon coil packs
Steeda T/A - uninstalled since in shop
MSD plug wires

The mechanic said its not registering the RPMs even after he replaced the sensor and put it back in the stock location.

*edit* - I think the one code was a 320

 

[00VERT GT]

damn stockers... how do you control the idle level then?
Guess you don't?

I guess it's all computer controlled.

 

[00VERT GT]

I'll try to get the codes from him a little later but in the meantime these are the mods:

1998 Mustang 5 spd GT, 36,000 orig miles
flowmaster cat back
screamin demon coil packs
Steeda T/A - uninstalled since in shop
MSD plug wires

The mechanic said its not registering the RPMs even after he replaced the sensor and put it back in the stock location.

*edit* - I think the one code was a 320

Did he replace the TPS sensor? Is that the sensor your talking about?

 

[pduffy02]

No, he replaced the crank sensor.

Also want to add that I think I had fried my spark plugs by setting the gap too big (.060, .005 less than recommended .065 by Peformance Distributors). The core of one of them was actually moveable like it had broken inside the plug. A couple others had brown burn marks on the insulator. He replaced these with new NGK TR55's.

Could these plugs have damaged something?

 

[pduffy02]

My Mustang is fixed!!!! I am so f'n happy! Apparently there was a broken wire leading to the crankshaft sensor that was shorting out. When I installed the Steeda T/A I must have pulled the wire to tight in order to reposition it. I'm just so ahppy now its been almost 2 weeks now. Only bad thing is that I have to reinstall my T/A and coils. Thanks for all the help.

PD

 

[lwkauble]

damn stockers... how do you control the idle level then?
Guess you don't?



Get him to give you a list of the codes and make a new thread here with those codes, your mods, and the problems.

AutoZone can pull the codes and print them for you for free.

There is a device called the Idle speed control motor. it's computer controlled and not adjustable externally.

 

[StangLou]

Well it did it again this am I dont know what it is exactly. Im starting to think adjusting the idle would do nothing to fix my particular situation. I started it up this am and it had a weird feeling shake to it. Not the normal smooth shake that normally goes with the car, just a odd continuous shudder. Put it in R and backed out, it was ok, still had the shake though. Made a few stop and turns, idle was fine, around 600-650, but it still had the shake. Got going straight on one rd in my subdivision which is a little uphill and it felt like I let off the gas. I put the pedal about 3/4 way down and nothing, I was still slowing, and my revs dropped to 500. I could hear my exhaust and it sounded like all the air was going out of the car . I put in the clutch, revs went back to like 650-700, I hit the gas and it responded. Shake went away then. Got to the stop sign and the shake was still gone, but my idle dropped to around 500. Put in the clutch, it went back up, I floored the gas once, then left the stop sign and the car was fine from then on Im confused as crap as to what it could be. Im guessing my shops idea of the tps going bad is the best bet. If it was the IAC it would have responded some when I hit the gas right? Im open to any other ideas guys

 

[Wi-Stanger]

Do you let your car warm up for 30 seconds or so before you drive or do you just start up and take off instantly? Also does it do that only when it is colder out?

 

[StangLou]

Normally I just start it up and go, but I have to find a good cd or whatever before I take off. Im guessing I sit for at least 30 seconds or more . Also, its not necessarily cold out when it does this, its just when the car has sat for a day or so. First time I noticed it, the car sat all weekend. We just drove around in my g/f car. This time, the car had sat since fri night, and did this sun am. So far it seems to do fine when I start it up every day.

 

[jstreet0204]

Your best bet is to find a shop or go to the dealer and have them hook up an autotap. Ortherwise you could end up chasing this problem spending money on parts you don't need. These engines depend on so many sensors to run correctly, it can be a real headache to figure out which one is giving you the problem.
Good luck!

James