Any clues as to why my check engine light on my Sonoma would go on after filling my truck with gas?

Question

Then after several fills later it has gone off, however crossing over some bumpy railroad tracks just the other day, it came back on and still is on. (Everytime I go to take it to the local Autozone for them to hook it onto their error code tester---the light goes back out --just before arriving there, so they can 't locate the source of the problem). The wiring has been checked and is working right, also the idiot bulb has been replaced. The truck has recently had an oil change, tranny flush, and tune-up. I just rolled it over the 100 thou. mark......

Answer 1

In addition to the cap answers, make sure you don't "top off" the tank...overfilling can set off the light also and could be a problem with the charcoal cannister purge system.

Answer 2

1st off... stop taking it to that shop for repairs. If they tell you they can't figure it out because the light goes out just before they get there, they are lying to you. The computer will store the codes for several restarts after the light goes off. There may be a problem that's hard to find causing this. But it's not because the light goes off before you get there.

There's a good chance it's the gas cap. Either you don't make it tight enough or it needs to be replaced. But there could be more to it than that.

Take it to a dealer. They will be more familiar with this problem.

Answer 3

I have a 2003 Sonoma, the engine light can turn on when the gas cap is not on the truck properly. You may just not have the cap on right or you may need a completely new gas cap. I've had the loose cap thing happen to me a few times.

Answer 4

It's the gas cap. On my Hondas, if I don't tighten the gas cap until the outer cap spins (and clicks), then the check engine light will come on. Try a new gas cap (it's cheap!) before spending any money trying to diagnose it. If that doesn't work, then find a good mechanic and let him figure it out.

My experience to date is that it is usually the gas cap.

Answer 5

I cant answer your question but even if the check engine light is not on when you have it hooked into their error code tester it should still be able to tell you an error code that the cars computer picked up . The mechanic should be able to tell you what that code means.I hope this helps

Answer 6

the gas cap is loose or has a leak in the filler area

Answer 7

gas cap is loose, make sure when you put it on you hear it click at least 3 times.