Well I was on the highway tonite around 9:45 and all of the sudden my check engine light came on! My DIC beeps and tells me to "Tighten Fuel Cap" and I tried that at the first chance I had to stop, but when I turned the truck back on, it was still there

It was too late to take my truck to Auto Zone for a free code check, so any thoughts on what it could be?

If you replaced the fuel pump in the tank, make sure all the lines for the EVAP system are secure as well as the seal for the fuel pump module.

I agree, try the seal at the tank. The Evap Purg pulses a vacuum to the tank to detect leaks and it gives the codes you see.

Im with the other s, check your connections at your fuel tank. You may also want to check and make sure the EVAP solenoid is set and sealed in the manifold. Sometimes the o-ring has a tendency to either not make it into the new manifold, or roll over upon install of the solenoid in the Radix manifold.

BTW how is the weather there? I have some family in Franklin and the wind is takin its toll on the homes in that area.

Thanks for the quick responses guys, I'll have to look at these things!

Weather has been pretty rough around here lately. I can't wait for it to clear up!!

I got that once. My gas cap O ring was broken. It didn't fall off when I was getting gas (which I do often) so I never paid attention to it. I relpaced the O ring and reset the PCM and the code never came back. Been several months....

Well I took my truck to AutoZone today so they could pull the code for me and it came up as P0455 - EVAP system leak, so I think Jeff, Joe and Brian win the "guess what caused my SES" contest!

Same code I got. Easy enough to check the gas cap, then crawl under thr truck.

Thanks for the heads up, I'll check it out!

Well the gas cap o-ring looks to be ok. It's in place and intact, so I don't think the gas cap is the culprit. Am I doing any harm to my truck by driving it while it has this EVAP leak? I've had no choice b/c it's my only mode of transportation at the moment because my g/f is out of town with her car.