OK guys, guess I have one last question.

When I close the gas tank cap completely and within 15-20 miles on the highway my gas tank creates a HUGE amount of sucking. I mean literally the plastic gas tank is being sucked in like a coke can would be at 100ft depth. intense negative vacuum pressure so much that the fuel tank suck/caves in, the fuel pump is being worked hard and the engine is being starved of fuel and when I open the fuel cap a LARGE amount of air is sucked in and the fuel tank will return to normal.
First, I review the forums and thought it was the front Purge valve in the line in engine bay(right behind and to side of Idle air control valve) so I replaced that.......Nope.
Then I thought the actual gas cap(WHY are these 50$?????). changed that.....NOPE
So now ive reviewed and perhaps its the Purge Canister BEHIND THE passenger side SIDE WALL?

At this point I have to barely close the gas cap, which means I smell gas in the cab if it sits for long, and I get a constant SEL for a "Large Evap Leak".

any help on fixing this? can I just instal a reverse pressure valve if my own design? Or is the only solution removing the whole side of the vehicle....if so I want to do the before I take to P&B.

again, thanks for the help, and Im pretty new to posting anything on a forum so apologies if I have broken protocols.

thanks again,
Doc

 

Anti-trickle valve might be blocked. It connects the fuel tank with the vapor canister and allows air to get into and vapors to get out of the fuel tank. It is closed when when topping up fuel in order to stop the pump when reaching the fill line. The function is described in the workshop manual in detail.