The truck starts easily idles fine but as you drive the truck and roll up to a stop sign or press in the clutch and brake to make a turn it will stall intermittently sometimes. As the rpms drop clutch pressed in it drops too low and stalls out no CEL
I've cleaned the throttle body, masf, new filter, spark and timing good.
also checked for vacumn leaks and checked the brake booster.
im thinking bad ground or throttle positioning sensor
any more ideas appreciated

 

I'm not sure, but I think that's because the idle is too high. When you press the brake, with the idle RPM too high, the ECU cut's the gas, since you don't want the RPM's high when the brakes are pressed to slow down.

Get a decent tachometer, like from Harbor Freight, and check your idle when the truck is warmed up to operating temp. IIRC, it should be 750 RPM. If it's much above 1000, this can happen. There's an idle adjust screw on the throttle body, just to the left of where the main air tube enters it. There's a large screw covering the actual idle adjust screw.
Quite often, the little rubber o-ring on the idle adjust screw (IAS) has degraded, or been damaged, allowing air to go by it, causing an increase in the idle RPMs. If/when, you go to pull the IAS out to replace the o-ring, screw it all the way down until it stops, not tight, just to the stop, making sure you count the number of turns it was from the bottom. The o-ring is readily available almost everywhere. Auto parts stores, hardware stores, etc.
When I put an o-ring on something, I always coat it with a very light, thin, coating of Vaseline. It allows it to seat better, and tends to preserve the rubber longer.
Once you have the new o-ring on the screw, screw it down until it stops, again, then back it off to where it was when you first started. It's a good starting point. Put the tach on according to it's directions, and let the truck warm up. Once it has, set the RPM correctly, then see what happens when you bring the RPMs up, then release the gas, and press the brake pedal, as though coming to a stop from street speeds.

Hope this is some help...
Pat☺

 

I had a problem where the idle hunts when I stop at the freeway exit ramp. Setting idle correctly fixed it.
I bought Actron CP7529 Digital Timing Light https://www.yotatech.com/forums/f116.../#post52399442

 

Nice timing light, RAD!

Pat☺