idle

1989 Mustang Gt 5.0 5 speed engine sometimes surges and then stalls sometimes runs perfect does anyone maybe have some info on this

I have the same problem with a 86 GT 5.0. The car starts than the rpms drop to 750 and then flutter between 500 and 1200rpm...car will stall out and it will stall out at stoplights unless I keep the gas on, car not running as smoothly as it was...I have a 5 speed as well. I don't know if it is an ignition module, spark plug, fuel pump or what..not fun to stall out at a busy intersection.

alright here we go. fuel pressure should be 35-45 lbs running, modules are a possible problem especially if the car has ran for a while. there was a recall for the ignition module for many years. refer to this website http://www.autosafety.org/article.php?scid=93&did=362. Ignition modules can be bought for $33 at autozone. check for vacuum leaks especially at the intake manifold, and change filters if needed (fuel filters should be changed every 12K miles) hope this gave you a starting place.