What is causing my check engine light to turn on under these facts?

Question

I have a 2000 Chevrolet Tracker 4-door 2.0 L Engine model. It has about 95,000 miles on it. When the fuel level gets down to 1/3 of a tank, the "check engine soon" light turns on. When I fill the tank back up to full, it goes off. Autozone told me the codes that came up for the vehicle were fuel injection and O2 sensors and that it might also be a loose gas cap. Since the gas level seems to be the trigger, is this most likely nothing more than a faulty gas cap issue? If you have any advice, please advise what it may be and how to fix it. I did try the fuel injection additive you can buy to put in when the gas tank is on empty every 5,000 miles to clean the fuel injection system, but that did not fix the problem.

Answer 1

True, a faulty gas cap will trigger a check engine light in your Tracker.

I would start by changing the gas cap - a cheap simple fix that could keep you from spending cash on items that aren't bad.

Make sure you tighten the new gas cap until it clicks a few times.

I'm not trying to insult you in any way, but I've seen people not tighten the cap all the way and end up with the same check engine light.

Answer 2

the scanner only points me to the problem area as a mechanic i then have to dig and look at many different areas to find the problem and digging gets expensive  

Answer 3

It is possible that when the fuel level drops below a particular point that there may well be air being drawn into the fuel system. If this is the case, the fuel injector code(s) and the oxygen sensor code(s) could develop. If the codes indicate a lean fuel mixture, this is indeed likely.

Beyond that, without actual hands-on, we are all just guessing.