Hello,

I have a 2001 Blazer 4 door with 185k and I finally decided to replace the charcoal canister thinking it was broken because there was a bypass valve on one of the air hoses. Well, I replaced it and plugged it back up with out the bypass valve and the truck just wants to die. It constantly hesitates and backfires and you hear this suction noise coming from the gas cap. Once you open the gas cap it sounds like opening a fresh 2 liter of pepsi lol. There shouldn't be any suction coming through the lines I don't think and everytime I drive with the gas cap open, the truck runs fine. For now, I put the bypass valve back on until I figure out the problem. Would this be the Fuel pressure regulator or the Fuel tank pressure sensor? From what I heard about the vehicle, there is something broken on the sending unit preventing me to replace the sensor but I am not sure.


If anyone has any ideas it would be appreciated.

Thanks,.

Robert

 

I would check to see if the EVAP purge solenoid is stuck open on the engine. It is located on the engine near the distributor.