In my 02` 4.7 I've never really gotten great milage, it usually is around the high 14 to 15 area. Recently I put on a new cold air intake and a new Flowmaster exhaust and the mpg stayed the same. Its been about 2 months now since that was done. Well in the past 3 weeks I have noticed a drop in mpg to mid 11 to 12, no its not much but when your best is 15, it makes a differance. The engine has no codes and does not seem to be missing or idling rough and I don't see any external leaks. Any thoughts? Engine miles, 187,500

 

Tune up?

 

Winter gas? Or are you leaning on it to hear the exhaust?

 

winter bland gas is a killer, same with my 2005 4.7 in the past couple of months

 

Well the tune up is good. Just changed both heads, plugs and a couple coil packs about 8 months ago. The engine runs great, no miss or roughness in sound or rpm. I did change my brakes around the same time that I put the new exhaust and cold air intake so maybe I have a brake dragging. As far as winter blend gas, I'm in New Orleans and I'm not sure if we get that gas here because we don't get that cold here.

 

Well I picked up all four wheels and the back spun freely but both of the fronts seemed to have too much drag on them. I could spin with one hand but I had to force it and when I took my hand off, the wheels would stop, while when I checked the back tires they would free spin about 1 revolution. So..... guess I'm gonna redo the fronts.