tighten gas cap warning

[detailjohn]

Getting this alarm tighten gas cap, and its tight. Check engine light is on.

Any ideas?

John:neutral:

[detailjohn]

06 gmc 4.8l cc 4x4

[retired2001]

I know that if the gas cap does not seal, it will throw off the emissions readings. There is probably a sensor that monitors the pres. on the fuel tank. If it is showing a bad reading the CEL might come on. Just a thought. Good luck!

[Cableguy]

I had that on my buddies 05 Jimmy. Replaced with aftermarket cap...problem fixed

[Samplemaven]

This just to get my three posts to remove sticky on home page.

[05-Burb]

Dont buy anything.

When this tank of gas runs out, buy gas at a different station, then put the gas cap back on as you normally do.

This should take care of the problem. Usually caused by a bad tank of gas, or the gas cap not put on tightly enough.

[Jimmiee]

Dont buy anything.

When this tank of gas runs out, buy gas at a different station, then put the gas cap back on as you normally do.

This should take care of the problem. Usually caused by a bad tank of gas, or the gas cap not put on tightly enough.

Bad tank of gas????? Please explain, Thanks.