I'm stumped - stalling/starting problems

Some days my 5.0 runs great, and other days it'll want to stall as soon as I push in the clutch. It usually starts right back up, but yesterday i got stranded at an intersection and had to call a wrecker. Then today it started up again. When it idles, the rpms usually go up and down until it stalls. When it wouldn't start yesterday, the fuel pump was not coming on and there was no spark. Surely its an electrical problem. I have a new ignition module on it. Only other thing i can think of is the computer. Any ideas??

Pull any codes yet?

The erratic idle is commonly linked to a bad TPS. But I would def. scan it for codes before I started replacing parts.

ok i'm gonna whore your thread up here...

my '89 5.0 acts like it wants to stall sometimes, and it has occasionally. i've already set the timing to 12* and cleaned the inside of the IAC motor with carb cleaner, which improved it greatly. also, the check engine light comes on after what seems like random lenghts of time of driving. i suspect my o2 sensors, especially considering the exhaust leak on the driver's side. next on my list is to check the voltage out of the TPS and adjust it. any other ideas?

Tried pulling codes - got nothing except for 'rpm out of spec. during idle' which I already know, I just don't know why. I'll check out the TPS, but that wouldn't explain why my fuel pump was not kicking on when it wouldn't start.

When the ignition is on it will not give me any codes at all, which makes me think maybe there's something wrong with the computer. But when it does start i can get codes while its running, but the only thing i got was that the 'rpm is out of spec. during idle' which i already know, i just don't know why. I wouldn't think it has to do with the TPS because when it desn't start my fuel pump doesn't even come on.

**sorry i put the same thing twice, my computer keeps messin up and I didn't think the first one got posted

what year is the mustang . it could be the fuel pump relay , eec relay or may be the pick up coil inside the distributer but the pick-up shouldnt mess with the fuel pump.the two relays will be the green and brown

its an '89. i tried a new computer - that wasn't it. i thought of the eec relay but i couldn't find it even after looking at my wiring diagrams. anybody know where it's at? i put a new fuel pump relay in already. someone else told me to check the pick up coil. it looks fine but like you said that doesn't explain the fuel pump kicking on. i'm still stumped.

i was having stalling problems in mine for a while. i checked the timing, which was off, and set it to 12* advanced initial. felt better but still had problems. took off the IAC motor and filled it with carb cleaner. let that sit for about 5 minutes and then shook it all out. reinstalled the motor and now it idles perfectly. hope that helps.

I'm not really sure where the IAC motor is. Is that the same thing as the air bypass valve? I did take that off and I cleaned it out. It idled pretty good after that, but I'm still not sure if I've fixed it because it only acts up now and then. Still don't know why it wouldn't start before. Could the IAC motor have kept it from starting maybe?

Well, today it was idling rough again. I'm gonna try changing the pick-up coil next and see if that changes anything.

have you timed the car lately? i'd double check the initial timing before i did anything worse. should be between 10 and 13 degrees BTDC

no, i don't have a timing gun on hand. but I have spent a considerable amount of time trying to adjust it by just listening to the engine to see if anything improved, but no luck there, although i know thats not accurate. i suppose maybe that would be a good investment.

Buy A Chevy!!!!

Can we say BAN!??

can you say 454 big block?

I put in a new pick-up coil and adjusted the timing to 14 degrees. Seems to be doing ok so far but when i start it the rpms jump up and then back down to below 500, then back up again and then it smooths out for the rest of the time its running.

Check the TPS. But also you may have a slight vacuum leak that fixes itself when the temp rises, due to heat expansion.

can you say 454 big block?

So explain something to me. Are you just a newbie that is trying to start a flame war and failing miserably due to the maturity of others? Or are you just a complete and total dumbass? First of all what does a 454 have to do with this thread in any way? Are you just trying to act big and bad and throw out large cubic inch BBC's because you think they are the biggest so therefore the badest. News for ya, thats nowhere near the biggest BBC. Try 572. But I am still wondering what chevys period have anything to do with this thread, much less forum.

So i've been drivin my stang now and then for the last couple of weeks and it seemed to be running excellent. Then a couple of days ago i went to drive it and it wouldn't start on the first try. Second try it started right up, but i didn't drive it. Today it wouldn't start at all after several tries. Same symptoms as before: no spark and the fuel pump isn't kicking on. I don't know what else to do. This is extremely frustrating. Another month and i have to put it away for the winter :disappoin .