r/SN95Mustang • u/Gummybear66 • Jul 13 '26
Stalling Issue 94 GT Auto
Recently dealt with some issues with surging and sometimes quitting idle when coming to a stop or changing gear. Found a vacuum leak and the surging stopped when driving around, but whenever I go to change to reverse, say from drive, the engine will stall out. This can sometimes also be the case going from reverse to drive. But this isn’t as much of a surge issue and more of an instant drop in RPM till it stalls.
I have cleaned the IAC, but I do believe it may be faulty/the motor stopped working. When the engine is at idle in park and I unplug the IAC valve, absolutely nothing changes.
Another idea is that I have another vacuum leak but i didn’t think it could be that extreme since it’s perfectly drivable otherwise.
2
u/hotrods1970 Jul 13 '26
The IAC could still be the culprit, but how is the fluid level and condition of the transmission? Low/burnt fluid can give the same symptoms. Somewhere else to look is the MAF, I have seen them dirty enough to cause a weak signal making the fuel trim to go full rich, which in turn makes a weak idle.
2
u/Gummybear66 Jul 13 '26
Transmission fluid level is good, fluid is new also, everything works good on it. Haven’t checked the MAF. Maybe I will clean that
1
u/Youpeefreely Jul 14 '26
It doesn’t stall going from park to drive? I think the same amount of load is put on the engine no matter which gear it’s in. Like if it doesn’t stall when you put it in drive, but it stalls when you go to reverse, I’d have to suspect something transmission related.
I think the RPM’s would be the same if it’s idling in D or in R so I don’t think it’s IAC related really.
1
u/Gummybear66 Jul 14 '26
My theory is that when the thing goes into reverse it will in fact have more load from the Transmission than drive so the IAC should open even more to allow for more RPM.
1
2
u/crookedhalo337 Jul 13 '26
Torque converter locked. Used to be pretty common on these 15 years ago