Chrysler Repair: 1994 Dodge Caravan-3.8L idles very badly, no codes, camshaft position sensor, crankshaft position sensor

Question
I have a 1994 Dodge Caravan with a 3.8 L engine, and it starts but will not run.  The Caravan ran well for 100 mile trip, and then I went to work and parked it, came back eight hours later and tried to start the van, and it would turn over, but did not idle without constantly goosing the gas pedal up and down, the moment the gas pedal was released the engine would die. The Caravan went from running perfectly fine to not running at all on the same day, which leads me to suspect an electrical component has failed.  I checked for codes with the on /off (three times) and all I get is a 55.  I have an Auto Xray scanner and it shows no stored codes.  I have unplugged the battery to reset the PCM and this did not fix it.  I have checked the coil pack (proper primary and secondary resistance), I have strong spark on all plugs, I have fuel (pulled the Schrader valve on the fuel rail and pumped fuel into a jar), I examined fuel for water or contaminants (none found), I've checked for any restrictions in the exhaust pipe (none found), checked the air cleaner, and also tried to start the car with the air cleaner tube off (still will not run).  When I say that it will start but will not run, it's as if the timing is  off or the engine is starving for fuel or air, it will even begin to backfire at the intake manifold, but it will not stay running, and is not anywhere near close to even idling. I suspect the PCM, which I have removed and looked at the connectors for corrosion or dirt (I cleaned them anyway). I do not know if the camshaft position sensor or the crankshaft position sensor could be a possibility.  But I do not understand if the PCM checks those in the first five seconds of cranking. I am baffled what to do next, other than to go buy a PCM and put it in.  What do you think?

Answer
Hi Greg,
My best guess is that your egr valve is stuck ajar. It is located in a pipe that comes from the right exhaust manifolt and is routed to the are under the intake throttle body. It has a round top, and between it and the body of the valve in the pipe is a flange with a rod that has a slot in it. That is the valve stem. Stick the tip of a screwdriver in the slot and move the valve back and forth against spring action that is trying to close it, in one direction. It should close to a full stop. Lubricate the stem where it enters the valve body with WD-40 and work it some more. Then see if it will start and run.
Roland