Where is the ECM on my 1992 Mazda Navajo?

What is your question?

Once it is warm and running it hesitates like it's getting no gas and when going up hill the engine light comes on until I let off the gas. Was told it's either the fuel filter or the ground to the ecm has come loose.

What makes this problem better or worse?

The warmer the truck gets the worse it gets.

How long has your 1992 Mazda Navajo had this problem?

It started after cleaned the motor.