Failing coolant temp sensors

[Dattebayo]

I have had to replace three coolant temp sensors since February... The engine starts to overheat after awhile, and then more progressively it has more and more issues starting when hot, but starts up immediately when totally cold. Then it moves to backfiring and dumping gas into the engine. I replace the sensor and all is right again, mileage improves drastically, then the symptoms start again in a few weeks.

Is there a condition that may be causing this problem that anyone is aware of? I own an '87 with the Z24i engine, and it's a California model.

[elwesso]

Have you ohm tested any of the old sensors coming out? Wondering if you have a short somewhere and it's making the sensor unhappy that way? Seems weird even with cheap auto-part store sensors that you'd replace 3 coolant sensors in 6 months.

[Dattebayo]

No, I never ohm tested any of them. It didn't occur to me because it always fixed the issue. What sort of thing should I be looking for?

[whomadewho]

Lot of could be? Good start - Focus on the cooling system. Make sure there is not a air flow restriction. Check the clutch fan. Stop by a service center and have the radiator checked with a infrared temp.gauge when you are experiencing an overheating episode. ( may have a defective gauge) Have the radiator cap pressure tested. Have the cooling system pressure tested - simple test to check for a bad head gasket. Possible on occasion the thermostat is sticking. And like elwesso mentioned you maybe dealing with a short. If you saved the old sensors try ohm testing them. Check the connection at the ECU and check for a bad ground.