I recently had the gas cap changed (told there was a vacuum issue) at inspection. It is very difficult to remove this new cap when I go to fill up. Now the car is experiencing episodes where it does not want to start (wants to turn over but it chugs, chokes). Once it's running, the car is fine, smooth, and with no acceleration issues.

I had another try and take gas cap off this am and it came off very easily!!! Could this new gas cap be creating too much of a vacuum while its running for long periods and then preventing it from restarting after being off for a short period of time.

I drove it for about 25 minutes, pulled into a store to shop, came out about 30 minutes later and it would not start. Next morning, started fine.
Same scenario the second time.

  • 3
    I think there may be another issue going on which is causing the over vacuum condition, which causes the gas cap to be very hard to undo. This same problem is probably what killed the original gas cap in the first place. I'm thinking the purge solenoid is stuck wide open or something similar. We'd need to know what year/make/mode/engine the vehicle is to help you further, though. Oct 14, 2014 at 18:35

2 Answers 2


There may be a breather tube that has become nipped causing the "vacuum". There will always be a design feature that keeps the tank pressure close to atmospheric as the fuel gets used so if something goes wrong with that a low pressure situation will be created


Gas cap very hard to remove, the problem is not the cap. The vacuum is most likely the fuel solenoid stuck open. Changing the cap will not remedy the problem. I will have my auto get this part replaced, soon.

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