Chrysler Repair: 2.4 liter, 95: codes 12, 23, 32, 42, 43, exhaust gas recirculation valve, exhaust gas recirculation

Question
Roland, I have a 1995 Dodge Stratus 2.4 liter That runs for about 15-20 mins., then as engine temps up, it misses very briefly, then stalls out. It will crank and at times i am able to keep it running, but very roughly by feathering the throttle very rapidly,then suddenly it will "catch" and run smoothly for a short period before stalling out again. It tends to do this when releasing the throttle to idle. If the vehicle sits for a period of time to cool down, it will start and run fine again for a similar period of time. Err codes pulled were 12,42,43,32,21,and 55 to end sequence. ASD, and ignition coil replaced to no avail. Please help. Many thanks, Dan

Answer
Hi Dan,
Taking the codes in order:
12 just says that sometime in the past 50-100 jey cycles the battery was disconnected.
21 says the one of the oxygen sensors is shorted to the heater voltage supply (it should not show more than 1.2 volts). This could be a failure at the fragile wires of one or the other sensors. Measure between the black/light blue and the tan/white (downstream) and black/dark green (upstream) wires to determine which.
32 says the exhaust gas recirculation valve is not responding as it is supposed to. I would start by lubricating the stem of the valve where it enters the valve body with some WD-40 and then moving the stem back and forth via the tip of a screwdriver inserted in the slot of the stem. If that valve is not closing (the spring-action of the stem tries to close it) when you take your foot off the gas, that will cause the stumbling that you describe.
42 says there is problem with the ASD relay control circuit. I would check the wire from the rearmost pin of the ASD socket to pin 67 of the pcm (dark blue/white wire) for continuity while shaking it, and also the front pin of the socket to have 12V on it at all times and then try shaking the harness.
and
43 is possibly saying that there is multiple cylinder misfiring.

I would check out the voltage readings of both the up and down stream oxygen sensors to see which one might be reading higher than 1.2V. These sensors come into play after the engine warms up so this is consistent with your symptom. I can't be certain if the oxygen sensors alone will solve most of the problem but those clearly have to be checked and replaced as necessary.
You can erase all the codes (except 12) by disconnecting the battery for a few minutes. I would give highest priority to the egr and the oxygen sensors. The ASD may be a stale code but probably is not the cause of the problems.
Roland