Hey guys -

Figured I'd post up the resolution to this.

Working on a friend's '90 convertible, he got to the point where he wouldn't drive it as it would intermittently buck and lose all power. When that happened, the check engine light would flash up.

I pulled the codes and found a code 9, coolant temp sensor.

We bought a new coolant temp sensor from Advance Auto Parts and also a new wiring pigtail as well.

Pull the alternator off and check it out. The coolant temp sensor for the ECU is in the back of the water pump housing, has a green square connector with a metal retaining ring. Unplugged it and looked at the plug. One of the pins was pulled back just a little bit, my guess is it was making intermittent contact and going open circuit.

I took the new pigtail connector and used a small pick to back the pins out of the connector. The stock connector had the pins come right out, I think the tiny plastic clips that hold them in place has disintegrated with time. Pushed them into the new connector, there ya go. They clicked in place and were good and solid.

The connector is a generic Bosch-style fuel injector connector so it's keyed for a fuel injector. I ground the key ridge off the new sensor before installing, the new plug went right on.

Code gone, car runs great, happy camper.

Figured I'd post this up for the next person to run into this .

Dale