Water in gas?

1997 saturn manuel wagon-My car starts fine, then when i make my first stop it doesn’t want to start again, and stalls when I try to shift into first. The mechanic ran all the codes and replaced the fuel filter and siad I should use dry gas. It does seem better till the tank gets i/2 full. I only use the car once or twice a week and do about 10-20 miles of stop and go driving

If I understand correctly the car runs fine until the tank gets down to 1/2 full?

The next time you have a problem, try removing and reinstalling the gas cap. If you hear a “whoosh” and the problem disappears, that’s a good sign that your gas cannot breath in through the charcoal canister and yuo’re developing a vacuum in the tank as the gas is pumped out that’s making it difficult for the pump to pump out more gas.

My guess is that at least one of the codes was an EVAP system code.

Post back with your results. If my suspicion is correct we’ll tell you how to fix it as well as suggestions to prevent this from recurring.

I like “the same’s” suggestion, but I would also consider that it may be a weak fuel pump.

Perhaps you could tell us exactly what codes the mechanic found (format = P1234)

the mechanic didn’t find any codes. Actually it mostly happens when it is less tha 1/2 full and it seems to happen at random times and most often when it is hot weather.
Next time it happens I’ll try the gas cap thing. should the car be running or not?
thanks a lot.

Doesn’t matter if it’s running or not.

thanks- i’ll get back to you