I have a 2003 Ford F250 4wd with an automatic transmission and 3:73 gears. It has low mileage and I want to keep it. How can I improve the gas mileage? I have researched the following modifications on the internet:
1. Cut a hole in the panel in front of the air intake on the air filter. (Force more air into the air filter.
2. Replace the air filter with a high flow filter like a K& N filter.
3. Install a throttle body spacer. (Creates a vortex that improves the air flow into the engine).
4. Install a less restrictive muffler.
Do these modifications increase fuel efficiency, if so how much?
Do these modifications cause any problems?