For a few weeks now my truck has been occasionally stalling upon downshifting and slowing to a stop. It doesn't stall everytime. The rpm's drop to around 500 ,then ramp back up to normal idle ,750ish. When it stalls, it drops to 500 but doesn't recover. I have noticed that it happens on downhill grades more so than uphill, and, seems like it happens more after engine has reached normal operating temp. It will start right up by key or popping the clutch with no problem. Anyone have any advice on what could be the cause of this? Thx, Bill

 

Hi Bill, There are a couple things that happen similar to my ole ford. When you are going along slow, does the throttle seem to act jerky or have a gap when you let off or set on it very easy. The early 99 have a TPS and a small micro switch below it. The problem is this this is a pot ?? which is like a rheostat that controls the throttle. I wears and at the bottom end will lose contact. I removed both switches and cleaned with CRC electronic cleaner and then sprayer dry silicon into both parts. Re installed. It cured the problem but didn't eliminate it. Came back in a week. So replace whole throttle pedal. Fix.
The other from a previous problem I had a IPR leaking. On the left head there is a pressure switch that is screwed into the galley that feed the oil to injector. Snap out this wire and see if it is wet. IF so, the unit needs replacing. The read the pressure that is at the galley to tell the CPM/IDM to fire injectors, if it drops below 500 to 750 PSI there is a problem. No fire. The HPOP could be wearing to a point there is to much drop in pressure to maintain correct pressure at the heads.


My old truck, early 99, F350, 7.3 w/ 6 speed manual. 326K tired but still trucking

Good Luck, ole man Rusty

 

I literally just went through a similar experience, mine even though it seemed so unrelated was my alternator. It would stall at lights and when I would put it into park the RPM's would rev it was also throwing the p0720 for the tranny, all is fixed now.