I have a 1985 Dodge D-150 pickup with a 2280 holley carburetor and about once a week it runs rich. I rebuilt the carburetor and was told it might be the engine coolant temp sensor. Any ideas on what could be wrong with this truck. All info is greatly appreciated.

Assuming the choke pull-off, float and fuel cut-off needle valve, and idle air mixture screw are adjusted properly, I would focus on the ECT Sensor.

This 2280 Holley carburetor doesn't have an air mixture or lean and rich mixture screw. It just has the idle screw for the gas pedal. The float is adjusted to 8/32 like it said in the rebuild kit. I'll check the needle vale and the ECT Sensor. Thanks for your input.

I meant to say, 9/32nd's on the float for the 2280 carburetor.