Check Engine Light During Long Drives

[teufelhunde]

I have a 94 Explorer 4x4, 4.0L V-6. During long drives, the check engine light will come on after about two hours into the trip. It will originally stay on for about a couple of miles and then go off. For the rest of the trip it will come on, stay on for a few seconds and then go off. This repeats itself for the remainder of the trip evry few miles. When this happens, it does run rougher. It first started doing this in 1995 while driving from NC to TX. But only on long trips. When it first happened, I took it into the dealership, they said there was nothing wrong with the vehicle. Of course it was the day after I completed the drive and the CEL was no longer on. Any suggesgtions?

 

[Gofast]

Same deal

Mine used to do that too. I think it was the highwat speeds for ectended periods that caused the check engine light to come on. I pulled in to a dealship with the light on and the codes read Lean condition. they reset the computer and it went away. They didn't know what to fix. No charge to me on that one.

I had an idea though. I went to Autozone and replaced my O2's both of them and the Fuel pressure regulator. I also replaced the fuel filter due to milage. Never got that light again.

I'm willing to bet you have over 70K miles and have not replaced the O2's ot the regulator? I had 165K miles before I did mine.

Good Luck

 

[teufelhunde]

Re: Same deal

THANKS FOR THE INFO. I WILL HAVE TO TRY YOUR SUGGESTION. I CURRENTLY HAVE 157K ON MY EXPLORER.

 

[Rhett]

That's exactly what my check engine did on a long trip in October. Since then I have not taken any long trips to find out if it will do it again.

 

[Triton46]

Same thing for me...only happened after 20 miles of highway driving. I took a trip to Pa and it came on after 20 miles and stayed on the whole trip. Got to Pa and changed the FPR, on the way home the light came on after 200 miles. Changed the O2 sensor....never got the light again.

If you have over 90K, I highly recommend changing the FPR and your O2 as a faulty FPR will degrade them. My CEL was sending a No O2 Sensor Present condition...so it doesn't have to read rich in order to be the FPR. My mileage was pretty crappy too and this was during the summer.