I have an 01 ford 4.2L 2wd. Heads were just recently replaced due to a tuliped intake valve. So it has all new seals from the heads up. Now the problem: In OverDrive at 75-80mph(2000rpm) under light accel(enough to keep you at 75-80mph on a flat road) it will buck and jerk like crazy, in 3rd at 67mph(2700rpm) it will do the same but not to the harsh effect as in OD. Now if you apply moderate to heavy accel under same conditions it will not happen, or if you let it idle from 85mph and drop down into the problem area. Runs great at all other speeds other than listed above.

Codes: p0340 - camshaft sensor circut malfunction < No Misfire codes, used mode 6 and still no record of misfire

Testing I've done: Taken the camshaft sensor out of vehicle to inspect for broken sensor, back probed the sensor, back problem the computer < both with a Lab Scope. Disconnected the MAF, EGR, and DPFE. Installed new spark plugs, sprayed water on the coil and wires, checked 02 sensors when acting up and .6 on both after Cat sensors, and .2-.8 on pre-cat, so they're normal. Power braked the vehicle and sprayed wires, no problems or misfires. Checked the IMRC for loose metal wires, still connected and not loose. Drove the vehicle at 75-80mph and demanded that the tcc be locked from 60mph+ in order to rule out a TCC shudder, also demanded no lockup of TCC. at 75-80mph in 3rd it will not buck/jerk, but will in OD. At 67mph in OD it will not buck/jerk but will in 3rd(not as bad as before).

I cannot figure it out, lend me some insight and knowledge.

I feel like selling this truck and buying a dodge...

 

Chilton has directions on how to test.This place might help you also
OBD-II Trouble Codes - DTC Codes Car Repair

 

Was at a loss today so I decided to check out the timing of the Cam sensor and low and behold it was off one tooth, someone was in the before and replaced the syncro & sensor but FAILED at timing the sensor correctly. Took it out and timed it to 126* clockwise from the block(of 54* before 180* of the block) and it has fixed the bucking/jerking issue. I just have a p0174 code now(Bank2 lean code) to work out and it'll be fixed.

 

new intake plenum rubber gaskets that go around the bolts fixed the p0174 bank 2 lean code, now all is good. fuel trims within 3 +/-

Also had to reset the KAM(Keep Alive Memory) in order to clear a p1093 code, followed by a drive cycle.