Greetings!
My F150 was dying at stop lights, anytime I got off the highway, or immediately after fueling up, and eventually showed a check engine light. After some trouble shooting, I figured out the fuel vapor purge solenoid was stuck open causing a vacuum leak. I replaced the solenoid and reset the computer, and mileage immediately went back to where it was new, 17 city /23 highway, but after 100 miles or so, it crept back down to around 12/16. I’m guessing there’s another sensor somewhere that’s still technically working, but is probably dirty and causing a bad read. Any idea where I should look next?
Jack Dobson
Did you put an OEM sensor in? Some generic purge valve from AutoZone won't do. It has to be OEM, not Chinese junk.
The purge valve is doing its job. I pulled the electrical connector and checked that it’s closed, and I’m not losing any vacuum there.
use a scan tool to look at your fuel trims and stuff like that
I don’t have easy access to one, and the only Ford dealer with techs charges $300 just for the time of day. I’m trouble shooting by unplugging and replacing to see what makes a difference, but I don’t know how many sensors make a difference… MAF, EGR, TPS, O2? I’m shooting in the dark, but I’m going to unplug the O2 sensor, reset the computer, and see where that gets me
the only Ford dealer with techs charges $300 just for the time of day
you can get your own for about $100 or less. So if it solves your problem, then it has already paid for itself.
We have a buying guide for diagnostic tools in our FAQ.
Great! I see a few different diagnostic readers. The Ancel, Autel, and the Launch. Will they all work?
As the article states, they will all do basic functions. The more you spend of course the more you can do with it. They will all read basic engine data.