Check Engine Light

Hi,
Need help trouble shooting a check engine light on a 96 GMC Jimmy.
It is my sisters truck, and about 3 weeks ago she ran it out of gas.
Ever since that time, when she fills it up with gas, the check engine light comes on, until the gas tank is about 1/2 full, then it goes back out. Anyone see anything similar to this before? I'm hopeful that someone can offer a suggestion to try before she decides to take it in and have a diagnostic run on it to see what code it spits out, any help would be greatly appreciated !! Vgolfmaster

Try reseting the computer to see if there were some bad signals. If the problem continues scan the computer, you may have a loose tube somewhere on the engine also. I just overlooked my friends car today and it had that exact same problem, and now it's fixed. Good luck.

i had a similar problem with the light always comming on. i found out that the gas cap was not screwed in all the way. now that light dosen't come on any more.

Originally posted by punk13rym
i had a similar problem with the light always comming on. i found out that the gas cap was not screwed in all the way. now that light dosen't come on any more.

Yeah, have to go wit this. P0440 is usually the code that is set with a loose cap and takes two consecutive non failure drive cycles for the computer to recognize the cap is tight. And you cannot reset the computer without using a scan tool.