My trusty '92 has developed an intermittent condition where when I first start it up from cold (first thing in the morning, for example), the MIL/CEL comes on, the radiator fan comes on and it runs rough and idles at a very low speed (like 5 or 6 hundred rpm).  The light goes off and everything returns to normal about the time the temperature gauge is coming up to the normal, just below midpoint, reading.  It does not do this every time.  Often it starts and runs normally. Non turbo EJ22, manual transmission, front wheel drive, 220k miles.  Any ideas?

 

Thanks,

Mike V.

Coolant temp sensor getting flakey poor connection.

^^^^ most likely

 

ECU doesn't know the engine is cold, so it doesn't 'choke' it with xtra fuel sent thru the injectors.

 

on your car, there may be 2 sensors. single wire I think is the gauge, 2 wire is for the ECU - maybe near each other on the coolant crossover tube?

Thanks Gloyale.  I think there may be two coolant temp sensors?  One for engine control and one for the temperature gauge?

Jumped the gun before I say Tex's message.  I will take a look and see what I got.

 

Thanks again!

Thanks Gloyale.  I think there may be two coolant temp sensors?  One for engine control and one for the temperature gauge?

 

 

There are 2. Just changed mine a few months ago. Sort of side by side under the intake manifold, passenger side. 

John - Were you having issues like I am?

Thanks Gloyale.  I think there may be two coolant temp sensors?  One for engine control and one for the temperature gauge?

Yes...one is a single spade to the gauge; the other is a plug connector to the ECU.

Pull history codes. Otherwise its just guessing.

 

GD

John - Were you having issues like I am?

Mostly just poor/low idle issues.  Like GD said, pull the trouble codes to pinpoint the problem.