Hey All,

Have a question that I have an idea on the answer to but not sure if I'm missing anything else that people more versed than me could point out. I have the above mentioned truck parked most of the time as the other project took precedence for a bit. Ever since I've had it, the fuel tank builds pressure while sitting. If I open the gas cap it will hiss out vapor for a good 30 seconds or so. I have seen some forum posts mention it building pressure while running and in between fill ups, but none while just parked and being started and moved for a minute or so.

Troubleshooting Steps:
It depressurized before swapping the sending unit
The rollover valve was checked and moved freely when swapping the sending unit, but still builds pressure
I have unplugged the vapor line from the rollover valve to the charcoal canister and it still builds pressure
I did throw a new push vent gas cap on it yesterday, and will check for pressure tonight when I get home from work.
At this point I should be looking at either the vapor line being clogged or the rollover valve sticking shut right? Not sure if there's much more to investigate in that system but wanted second opinions because I feel like I'm going crazy lol

 

I had a similar issue, The charcoal canister was filled with water. The vent where it pulls in fresh air (for the evap system) has a rubber piece on it to keep out water(located on the drivers side near the brake booster). Mine was gone allowing water to get in and clog the canister. The screen that keeps the charcoal in the canister has been known to disintegrate allowing the charcoal to get sucked up in the line. The canister is where i would look.