Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Why did my MPG drop? I?
I have a 2005 F150, 5.4 engine and 130K miles. I just had a tune up and MPG dropped from 14 to 9. Just looking for ideas before I go back to the mechanic.
4 Answers
- The DevilLv 74 years ago
Do an OBD2 code check. The fault will be indicated by the trouble code. If there was no trouble before the tune up, I'd guess, wrong spark plugs, wrong gap, or a couple of plug wires are mixed up.
- ?Lv 64 years ago
I agree with KY Clay. Did you get this truck used? You might check to see if there's an aftermarket chip in there for the computer that didn't get reset with the tuneup.
- ?Lv 74 years ago
Possibly the wrong spark plugs installed or gapped incorrectly. Vacuum hose unhooked or broken. Defective O2 sensor if the check engine light is on.
- 4 years ago
What do you mean by tune up?
Ford engines are really picky with oil used and should only use a Ford oil or something that says recommended for ford's on it. My friends ford fiesta wouldn't drop below 1000rpm with 10w40 in but with ford 5w30 dropped to 700 rpm idle
