Hello,
I was wondering if there were any ways to improve fuel economy with a stock engine. The owners manual says even in top condition, the fuel economy on this truck on highway conditions sits at 16 mpg, about 14 mpg for city/traffic. Mine gets with combined conditions roughly 13.1 MPG. If I need to mod or change anything, that is fine, but I want to keep the original engine, which is the notorious 5.4 3 valve Triton. As far as I know, everything from the fuel system to emissions is stock. It runs 87 unleaded but even this is kind of hurting my wallet. I will say that it throws a P0420/430 code indicating that the CAT on both bank 1 and 2 are below threshold. However, I also know I have an exhaust leak and wonder if this is causing the code (I've already pressure tested the CATs and it passed inspection). Do you think this may why the fuel economy is low? Also, any suggestions for improving overall fuel economy in general?
Below is the vehicle information
Lincoln Mark LT 2007
Transmission: 4R75E 4-speed
2WD
141k
Not only can the exhausted cause a cold it can also cause bad gas mileage I would start by fixing the leak first and praying it hasn't destroyed the cats because if they could clogged up from carbon then they need an expensive replacement
Unfortunately, those are big heavy trucks and as they age, similar to any other car, you can not expect to have the best performance regarding the gas mileage. With that being said, try obvious stuff; cleaning my the MAF sensor and throttle body, use clean air filter, adjust the tire pressure correctly and most importantly drive conservatively.
About the CAT, the leaks can trip the code.
