I have a 95 F150 300-6cyl and auto tranny. I put a 160 thermostat in it and I think my mileage dropped alot. Should I go back to a 180 or 195 degree thermostat? Also, I thought about gutting my cat for better exhaust flow. My state doesn't have emissions. Any advice would be great. Thank you.

Drew

 

Put the 195 back in. At 160 the engine never gets to the warm run temperature that the PCM is looking for so it remains in the cold start mode which is grossly rich. This wastes fuel, increases emissions, causes excessive engine wear and adds no HP whatsoever.

 

I don't know for sure if this is correct but a mechanic at a dealership said that if the engine does not get up to 180 deg for a few minutes then the engine does not get hot enough to burn moisture out of the oil

 

Someone over at a Thunderbird/Cougar message board had moisture in the oil and I think he had a too cold thermostat.