My '90 has been running a bit weird lately. Initially I was losing power just a bit while cruising at ~ 40 mph.

Today I pulled the car into the driveway to check some things, I just let it idle for 5 minutes while I listened to the in-tank pump via a length of hose stuck in the filler spout. The engine began running rougher and rougher almost stalling only to catch again. It did this for 1 minute or two and then it stalled. The engine will 'catch' whatn I try to start it back up only to stall a second later. It will run (rough) if I keep my foot on the gas.

I have:

*cleaned the throttle body and checked the tps switch. (clicks right when you move the throttle)
*Inspected the main air hose from the AMM to the throttle body (looks good)
*Disconnected and reconnected the AMM
*checked and cleaned fuel injection related fuses
*In tank pump sounds strong
*Main pump sounds strong.
*can't check discharge from the fuel pump relay, but I did hear fuel rushing back into the tank when the car was running and I was listening to the intank pump.
*removed and cleaned IAC valve, bench tested with 12V and it appears to work.

So basically I'm stuck where the car will start as normal, ramps up to 1000 rpm and then just dies.


Other Possibilites:

Fuel system relay (replaced 60k ago)
crank position sensor (might be 230k old)
coolant temp sensor (idles when cold but not when hot)???

Thanks in advance for all responses.
Matt

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'90 245 224k, '93 945 184k