I changed the ECU on my 92 Civic. The A/C was not working properly. I was getting 39mpg without A/C. I now get 32 MPG with A/C. Doesn't this sound like a large drop in mpg? I figured 3 mpg maybe but not 6! I am at 4500 ft elevation and I do not know where the ECU came from. Are there tweeks I could/should make to improve the mileage?

Thanks

 

what ECU did you put in? What is the code of the ECU? 6 MPG depending on driving style, conditions, is feasible.

 

I will have to look at the old ECU but it is the same model number. What do you mean by "code"?

Thanks

 

6mpg drop is what I would expect if you're driving in town with the A/C on all the time, highway driving should be slightly less.