I have a manifold leak that I found when replacing cam phasers on my truck. It seems this winter my gas mileage has been terrible to say the least. This weekend I plan to clean throttle body, maf, and new fuel filter for the trucks 47,000 miles first time. Probably will help my situation some.

I'm just wondering if a manifold would likely cause any decreased mpgs? I have gone from getting around 16-17 in the warmer weather to only about 10. Seems like a drastic drop, maybe not.

 

yes, it could be allowing your o2 sensors tell the ECM to add fuel making the truck rich


also check your trans mount

 

Okay, well when I change the fuel filter this weekend I'm gonna try to get under there and figure out whats up with the manifold. Then go from there to fix it. Just to dang cold out right now for me to have the motivation to mess with it.