SITREP: Engine drops to idle, CEL ("Service Engine Soon") comes on. Depressing accelerator once or twice brings no response. Usually the engine drops to idle about 1 second before the CEL comes on. Usually after 3-5 seconds the accelerator will respond normally, the CEL goes out, and the truck resumes normal behavior. I can occasionally duplicate it deliberately by pulling away from a stop, backing off the gas when I reach 25MPH (speed limit).
I have not experienced this enough yet to see if it does it while cold.
Another recent symptom: At speeds under about 35 and under light acceleration, the transmission bucks and kicks. It appears to be the transmission shifting in and out of 2-3, or possibly OD. It may instead be the transmission responding to the engine, rather than the reverse.
No flashing lights.
No modifications.
No chips, but it does have TRANS TEMP, BOOST and EGT gauges. Max trans temp is 140 or so (160 under heavy tow), max EGT is 600 under hard acceleration (800 under heavy tow), max boost is 18 only under hard acceleration or heavy tow.
Starts and runs otherwise fine. (Note: Boost source is a welded nipple into the passenger side aluminum IC pipe, the heater is still in place.)
No recent changes, except oil change 4500 miles ago (it and the transmission are full) and the brake wiring recall 4 months ago.

2000 7.3L F-250. Driven daily, 20 MPG empty, no other known issues.
The Actron code reader I have sees no stored or pending codes, but does communicate with the truck.

Your help is greatly appreciated.

 

It does not sound like that Actron code reader will work for the truck. If the check engine light came on you should have codes. Try unplugging the icp sensor and start. It should throw a 1280 code.

 

Sounds like the Throttle Position sensor On the go pedal , some have had luck with contact cleaner ...If it starts out that way , may be the idle validation switch...Check the wiring to the pedal , make sure the connections are clean & tight ...

 

UPDATE:
Clay agrees it is most likely a TPS. He is sending me one to test.
Excellent idea to test the Actron with the ICP unplugged - I will try that tomorrow.

Updates will follow!

 

Yup, I agree with the TPS.

 

I was also thinking the tps...Do you have a digital ohm meter you can do a sweep test and look for dead spots? Let us know what fixes it....How far are you from me..I have a spare you can test with if its faster than Clay's...Im at zip 29744 Good Luck Matt