fuel cap and check engine light

[ahargrove]

Hello all.
I have a 2007 explorer xlt, 4.0, 4wd with 72,000 miles. The fuel light came on first, followed by the check engine light. Both Autozone and Advance Auto's code readers say the problem is at the fuel cap. I have replaced the fuel cap and fuel filter but the lights have not reset. I understand they should reset if everything is fine within about 3 driving cycles. The new fuel cap was put on well over a week ago and I have driven well over 200 miles since. The fuel filter was put on about a month ago when I put new plugs and wires on.
Any suggestions on what else to check? I read somewhere a few months back that someone had a similar issue but their idle was irregular and it was the fuel pump. My idle seems fine, maybe a little variation, 100 rpm, give or take.
Thanks in advance for reading and any help you can lend.

 

[edwx]

If it were mine, I'd have the code checked again. Note what the code is, and post it on this forum.

 

[IndyDJs]

I have the exact same issue. Mine is an 06 xlt with the exact same symtoms. Any help would be greatly appreciated.

 

[Town]

In the first post there were 2 apparently different issues:
1. fuel light on that normally indicates a low fuel level in the tank;
2. "check engine" light on that was diagnosed as a loose/missing fuel cap (dtc P0457),

Do you have both of these? Has your fuel cap been replaced.

What is the fuel gauge reading when the fuel light comes on?

There are a huge number of diagnostic trouble codes (dtc) covering the evap system. The code for a missing/loose fuel cap just means a large evap vacuum loss, but there are lots more codes related to vacuum loss and other evap system problems. See if you can get the dtc read at a place that does not charge for this service.

The electronic throttle control should hold engine speed steady at idle, so any variation may indicate a vacuum leak. The evap hose is subject to failure due to fuel vapours breaking down the hose and causing cracks and holes.

Good luck.

 

[Beargap]

If it were mine, I'd have the code checked again. Note what the code is, and post it on this forum.

Had a code that there was a leak in the evap emission system on our 290K '97 Explorer, often seen from a loose fuel cap, but that wasn't the problem. I reset the code by disconnecting the battery, and the code didn't come back. However, about a week later noted fuel leaking under the car while refueling. Turns out the fuel filler neck had rusted at the connection with the rubber hose that goes to the tank. In fact, it rusted completely through. A replacement was not hard to do (google this, there is a good video showing the procedure) and all is well again using a part from a junkyard.

=Vic=