Service Engine Light

I have a 1998 Chevrolet Lumina with a 3.1. I have ran codes for the vehicle and changed both oxygen sensors. But everytime I fill it with fuel, no more than 10-15 miles and the service engine light comes back on. I run the codes again and says the same thing. Exhaust leak, oxygen sensors, not enough air mixture.

I can clear the code and poof it stays out. But when I put gas in it again, poof there is the light again.

It is getting costly to have codes read and reset. What or where else can I head to ? Is there a sensor for the fuel somewhere that can be changed? There are no exahuast leaks, car run magnificantly and brand new air filter and fuel filters installed.

Someone with a direction to go would be great. Thanks jj

I believe you have a bad gas cap, or you're not tightening it to at least 3 clicks. If you do not tighten the fuel cap properly, or if it is bad, it will trip an emissions code. Try resetting the code and tightening the gas cap properly. If that doesn't work, get a new cas cap. If that still doesn't work, you may have a bad fuel purge valve causing excessive pressure to build up in the fuel system, Good-luck and let us know how it goes

wipe the threads clean on your gas cap, sometimes they get dirty, and you click it 3 times or even more, and it still isnt tight, and allows gas to evaporate. When you fill up, dont go by the book of 3 clicks, do like I do and wrench the sucker, like a million clicks. Good luck

Arent there two O2 sensors on those? One on the manifold and one behind the cat?

Changed out the cap last night and have to go get the code cleared. ALready changed both o2 sensors. I am guesing next step is EGR valve since the swich is intergrated on the vavle. Wish me luck.