Chrysler Repair: 92 2.5L 4-cyl: Lurching issue, exhaust gas recirculation valve, chrysler lebaron

Question
Roland - I'm hoping you can help me with this bizarre, continuing problem.  It manifests itself in a few ways.  Most often, I'll be driving on the freeway at about 60mph and suddenly the car starts to lose acceleration if I keep my foot steady on the gas pedal.  It will drop down to about 50mph and then a surge of power brings it back up around 60.  This process usually continues for around 15 minutes, and then suddenly the problem goes away and the car drives fine again.  I've found that if I fiddle with the gas pedal and move it back and forth quickly while the problem is occurring, the car stays at a fairly constant speed and doesn't lose power.  Thus, moving the gas pedal a significant distance almost always disrupts the slow-down, so keeping it moving helps alleviate the problem.  Ideally though, I could fix it.  The fuel filter has been replaced and I've been running injector cleaner through the fuel system for an extended period of time.  The problem has also persisted through a standard tune-up of plugs, wires, distributor cap and rotor.  What direction should I go from here to fix the problem?  Thanks.

1992 Chrysler LeBaron 4-door sedan
2.5L SOHC non-turbo

Answer
Hi Bill,
I would suggest that you try for fault codes using the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat to be sure of an accurate count set. Then group the numbers in pairs in order of appearance to form the two digit numbers which are the fault codes. The last number will always be 55, the code for 'end of readout'. Then write back with the results or go to www.allpar.com/fix/code.html for a translaton. We'll go from there.
About the only other item that is not well monitored is the exhaust gas recirculation valve which is mounted on the rear side next to the firewall, toward the front of the engine. Notice it has a flange separating the valve body from the round vacuum operated actuator on the top. In that flange you will see the valve stem, a rod with a circumferential slot. Use the tip of a screwdriver to move the stem up and down, against spring action which attempts to close it. If it seems sticky in moving to the closed position then spray some WD-40 on the stem where it enters the valve body. Then work the stem to loosen up the action. If that valve were to be sticking it might on occasion fail to repond and that would cause a temporary lean mixture which might explain the lurching.
Roland
Roland