My '87 240 has been having an intermittent stalling/bucking/no start condition for quite a while now. It has problems when cold (especially when raining) but runs and starts OK when warm.

I've replaced just about everything, including both fuel pumps, fuel relay, fuel injection fuse and holder, both fuel filters, the little hose on the in-tank unit, distributor cap and rotor, plug wires, coil, temperature sensor, fuel pressure regulator, AMM, ECU, cleaned the throttle body, checked for leaks in the air hoses to the throttle body, fixed vacuum leaks, made sure the distributor is dry, and so on. About the only things I haven't done are the ignition computer and the engine compartment wiring harness.

When it won't cold start, it will often start (grudgingly) after I disconnect the AMM connnector, crank it, and then reconnect the connector. This makes me think it's a poor connection here, but I've cleaned the AMM contacts as best I can.

So:

1) The key symptoms are very poor starting in the rain, and how this responds to disconnecting and connecting the AMM.

2) How can I clean the AMM connections better? Also, would this problem be consistent with a bad wiring harness (something shorts out when wet?) Problem occurs even before driving, so no water should be splashed up anywhere...

Thanks guys,

DS