Chrysler Repair: 96 Sebring hard start, dies quickly, obd ii reader, crankshaft sensor

Question
QUESTION: The car "died" at the grocery store- the starter would turn over the engine, but no spark.
the computer codes were 12 11 55

I had it towed to the repair shop where they replaced the crankshaft sensor. It now started hard, but ran extremely rough (missing, backfiring) would not idle.

The repair shop wanted to keep replacing items, but they admitted they had no real idea what was wrong, so I had the car towed to my house.
after resetting, the computer codes were still 12 11 55

I have since replaced the:
Idle air motor/valve
Distributor
spark plugs, ignition wires, cap & rotor

I have looked for any kind of vacuum leak- none i can find
I watched the alternator output with various loads and no apparent voltage spikes 13.9VDC
At #1 TDC both camshafts line up perfectly with their marks. The timing belt is in very good condition.

after resetting, The computer codes are still 12 11 55
I understand code 11 to mean bad crank sensor or bad cam sensor or timing belt

I checked the fuel pressure last night:
at key "on" it came up to 38lbs and while it was running (missing, backfiring, etc) it went up to 54lbs and always stayed in this range.

after some reading, i was going to suspect the upstream O2 sensor next- can i test this?

can I recheck the crank sensor with a volt/ohmmeter? how?

Thanks for any help/ideas.
Steve.

ANSWER: Hi Steve,
You have done a good job seeking the problem and reporting the results. I would suggest that you take a look at your egr valve to see if it might be clogged or the stem is sticking in an ajar position. Spray the stem where it enters the valve body with WD-40 or similar solvent.
I assume that you have disconnected the battery for a few minutes to erase the codes, so that you still are generating a "fresh" code 11. You are correct about the multiple possibilities for an 11 code according to my '96 manual for the 2.5 V-6. You might get a specific indication by using an OBD-II reader to separate the timing belt (1390), from the no crank sensor (1391) or cam/crank sensor intermittant, or too much variation in crank target windows (1398). You can observe the output signals from the sensors by probing the wires with fine pins, turning the engine via the bolt on the crank pulley, and with the ignition in the run position. Measure between the gray/black and black/light blue (crank) and the tan/yellow and black/light blue (cam) sensor wires. The voltage should oscillate several times between 5V and 0.3V for every full revolution of the crank. You might try shaking the harnesses to be sure that there is a good connection between each sensor and the PCM. The signal wires are on pins 32 and 33 respectively of the black plug, while the ground wire is on pin 43 of the gray plug at the PCM if you want to check for continuity.
The O2 sensor should read around 1V, but I suspect that is not the problem because it would set a code, and also because it doesn't come into play until a few minutes after starting the engine.
Please let me know what you find out.
Roland

---------- FOLLOW-UP ----------

QUESTION: Thanks, I will get on this tonight. I was unsure of whether the 96 model would take the OBD-II reader. I have seen them with "16-pin interface", do you know it this is what fits the mitsubishi 2.5L v6?
Roland, you are a great help, thanks again.

Answer
Hi Steve,
'96 was the year when most models came with the OBD-II system and the associated 16-pin plug. Take a look for it under the dash at the lower edge near the steering column.
But try the other tests before investing in a code reader because you still have the ability to use the key to get the OBD-I system codes.
Roland