Chrysler Repair: Chrysler T&C hesitation, exhaust gas recirculation valve, throttle position sensor

Question
2000 Chrysler T&C 3.8l. The engine hesitates when accelerating at different almost random points along the powercurve. Have replaced fuel filter, camshaft position sensor, spark plugs & wires, throttle position sensor.  Took it to local garage that has two fairly sophisticated computers.  Their computers were unable to interface with onboard computer (pcm). They wondered if pcm had ever been flashed. We have owned vehicle for 6 years and has not been flashed. They suggested taking to a dealer. Wondering about replacing pcm. If pcm is replaced how does this need to be synced with other computers (i.e. transmission, body control).  Thanks.

Answer
Hi Steve,
Have you tried the ignition switch technique to get fault codes from the pcm? Turn the key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see if the mileage changes to show instead 4-digit number prefixed by a P. If so, let me know them and we'll go from there. Also, the hesitation may be caused by a sticky exhaust gas recirculation valve which has to close tightly when you accelerate or the mixture will be too lean resulting in hestitation. The valve is located near the throttle body air intake at the end of the engine, mounted in pipe that recirculates exhaust gas from the rear cylider bank exhaust pipe back around to the intake manifold. The exhaust gases have some fumes that can plate out a crud on the valve stem. The valve proper is mounted horizontally with the stem visible in a space between the body of the valve (mounted on the pipe) and the round top of the valve which ix a flange and so if you look carefully you will see a metal rod (stem of the valve) with a slot around its circumference in the flange area. You can take the tip of flat blade screwdriver and insert it in the slot and then lever the valve back and forth to check if it is moving freely (against spring action in one direction) or not. If it doesn't seem to close easily with the help of the built-in spring, then I would spray the base of the stem where it enters the valve body with solvent from a pressure can (such as WD-40 or carb cleaner) while moving the stem back and forth.  Then see if that solves the hesitation issue.
If you change the pcm it will require that vin numbers be input for proper operation of the security system and some operating parameters. But I would not do that without a firm code of a failed pcm.
Roland