Stange stall?

Got a problem, very wierd.
This has been going on intermitantly for a few months now, and now that its been cold out its been acting up a little more.
Ive been starting it up in the morn to go to work and start to drive down the street and all of the sudden it stalls, but DOESNT ever shut off the engine. So a few times i have pressed the gas all the way in when it does this. It makes no difference to wake it up out of its trance like state but when i do push the pedal down and it comes out of it i feel a clunk or a knock at my feet. Ive taken it in to see what was wrong with it, but they have never been able to re-surface that problem. And they say its running perfectly.

Its almost as if the engine stumbles.
Since then ive done a full tune-up, replaced both 0-2 sensors, temp sensor, checked the TPS-looks fine and had the fuel pump checked, everything is running nominal. I even have a scanner that tells me exactly how the engine is running and has never thrown any codes.
1997 4.0L It has an automatic Trans.
Someone stated that it could be that my TPS having a dead spot in it causing my TB to back fire.
If anyone knows of some tests to run to figure this out and narrow it down, please notify me.

It never does this if i warm up the engine first.
This is a strange issue. :banghead:

I always stall a little when I get with some strange......





Hale

There's a resistance test or whatever to do for the TPS.....so grab a meter and click search, because I'm not sure what the numbers are.

did you notice if it happens at any particular rpm? i had a similar issue on my 91 at around 2500 rpm. it turned out to be the cam sensor in the distributor. i believe that particular sensor helps with the injector timing. not as important as the cps. but mine would do a similar drop out and buck and feel as if it is stalling or dying. no codes from it either. just a thought.

Thanks Mikey and Blaine, very funny Haleyes.
Mikey after it shifts into 2nd gear it does this. Only on a cold takeoff though.