hello i have a 88 gt 5.0l high output. when i start my car cold it idles fine but when i start it warm it idles real low and sometimes stalls. iam just wondering what is wrong. my buddy thinks its something to do with the vac but i don,t know........... anyone

 

If its only happening during warm days it might be cooling related

 

sorry i ment to say it only happens when i start my car within a hour of driving it. the weather has no effect on my idle what so ever its just when my car is warm from driving it one guy says vac leak
another guy says cloged mass air flow sensor

 

hmm thats interesting. I've never heard of a problem like that before.

I wish i could help more I'm sure someone here will be able to help though

 

right near your throttle body there is a sensor with a metal piece that usually is dirty...maybe it is called the mass air flow sensor. I had the same problem, and I took the metal piece off and cleaned i with carb cleaner, dried it off, then put it back together...problem solved...I just forget off the top of my head as to where precisely it is...I think it may be right near the throttle positioning sensor..

If it only happens when you first turn the car on, I doubt its a vacuum leak...but I'm no mechanic

 

Assuming the 88 Mustang he has is not from california, and also if the previous owners have not done a swap, there should not be a mass air low sensor on that engine. However, if it indeed does have a MAF sensor, then make sure you know how to properly clean it. The idle- when you say it goes lower than normal, is it also rough? or still smooth, but just at a lower RPM? And also, could you give us the rpm range it falls down to and whats "normal" for you?

 

Could be the TPS going out or cruddy? Throttle Position Sensor right on top of the Throttle Body. Mine did that on my 87 a whilke ago...

 

Sometimes it can be the position of the TPS...if it somehow moved from the angle it was at before that can affect it as well..

 

my car idles just under 1000 rpm normal. but when it idles lower its 500 rpm and it goes from 500 to 900 rpm back and forth . it runs smooth with the lower idle and it does not have a mass air flow sensor thx

 

thx for the help but i figured it out it now runs fine no probs

 

so what was it?

 

what was it?

 

It must have been the Idle Air Bypass Valve mounted next to the throttle body. They plug up with crud and need to be cleaned with carb cleaner from time to time. You take it off and flush out the ports and valve and put it back on. If that doesn't clear it up right , replace it.

 

well, at least its solved

 

he still hasn't said what the problem was

 

hmmmm

 

ok first i bought a new TPS and no go.then i took the mustang to work and changed my alt still no go.then i changed my injectors/my boss guessed right it was the injectors
and now it runs like a dream
but anyways thx for the help everyone
and sorry for taking so long to tell u guys what the prob was

 

did you go with 19 pound injectors, or heavier?

 

i just stuck with the stock 19lb injectors

 

Glad it worked out for ya!!