Our Tahoe has almost 110,000 miles on it. It has been very reliable. Recently it started throwing emissions codes, which we were able to read and reset at the local auto parts store.

The codes have been all over the place, never two codes, just a single code each time,

P0455
P0496
P0442-00

I have cleaned the gas cap seal and lubed it. The system is building pressure, which according to the codes it should not be doing, so if the codes are accurate i realize i may have an intermittent problem. Hopefully someone here can help us shed some light on what it may take to fix this problem.

Occasionally when we remove the gas cap there is a large release of pressure. and almost every time we fill the tank, the truck acts as if it is NOT going to start. The sound is as if the autostart feature holds the starter in, and it sounds like its running on just a few cylinders. This rough idle only lasts a second, and has cleared up each time and the truck starts and runs fine till next fill up. We have never had any issue with putting fuel into the tank. My wife generally runs the tank down past empty. Since we had the plugs and wires replaced about a month ago, we have made a conscious effort to fill the tank before it reaches 1/4 tank.

Any ideas from the experts would be much appreciated.

Thanks,

Yamahauler99

 

Welcome to the forum I'm moving your post from the general tech to the Tahoe section...
Rarely is the gas cap ever the problem, most often its the vent valve or canister issue...

Give this thread a read https://chevroletforum.com/forum/tah...5-codes-32465/







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