I have a 93 150 with a 4.9l engine and automatic with OD. At cold startup it hunts for a slow idle, sometimes stalling. It'll take about 1 plus minute to find a stable idle speed. Then it's ok. Also when shifting from one gear to the next I get a momentarily power loss. It just doesn't shift from 1-2 or 2-3 without somewhat of a power loss upon shifting. I have replaced the upper to lower intake gasket and the throttle body gasket. Not sure what this might be, but I do not think it's a tranny problem. It seems engine related. If I really step on it after a shift it will pickup. It just doesn't seem normal change of power on shift. Any suggestion anyone. I appreciate any help.

 

Not 100% sure but if I were to guess it sounds like the torque converter may be having issues .

 

MMMM, that's a thought. Seems kinda logical. I wonder if There is any way to check that. Without pulling the xmission. Of course that wouldn't be the hunting idle problem, but makes sense for the power loss at shift.

 

You could have a vacuum leak in the harness somewhere or one of the resovoirs could be leaking, but also pull the codes to see if the computer is having trouble with a sensor maybe, if nothing else you'll eliminate a bunch of possibilities.

 

There were no codes. I've looked for vacuum leaks, could find one.

 

Actually it can cause the hunting too, if there are issues internally causing the load to change while turning the pump even in neutral.

Quick story: When I was young working in a garage there was a really nice 6 cyl Powerglide Nova that would stall every morning at the stop sign across the street, we all had a good laugh when it happened. One day when the owner came in to buy gas he came in and asked if we could fix the problem (stalling), of course I jumped up and volunteered. When I opened the hood to my dismay the owner had already spent some $$$ trying to solve the problem, new carburetor, new distributor even had a valve job despite the low mileage (35k or so). I convinced myself it was something someone else had missed in a detail, a week later no luck. I drove the car to lunch to meet a friend, he was real sharp automatic transmission guy, he saw the Nova and asked if it was mine. I told him all about what went on and he kind of laughed, he said come down after hours and he would help me fix it.
Turned out we pulled the trans and replaced the converter, none of the guys (including me) ever considered what kind of havoc a bad converter can create, in this case the car would run perfect otherwise.

 

Very interesting story. I don't drive the truck every day. So I have time to play with it. Think i'll check on a few more things. Timing, tune-up and such. I'm not at all against pulling the tranny. The converter seems expensive for this OD xmission. $275 at rock auto. I've been researching a stall test of the converter. Don't quite get it yet, but you chock the wheels, put the brake on, hold the brakes, the put truck in drive and go wide open throttle. Not sure what's suppose to happen then.Other than blow up the transmission. Is it suppose to stall or what? It did say not to hold it there long due to heat build up. Any other tests for the coverter out there?