stalling at 3000 rpm

[alldodge]

but why does it work fine after vent hose removal?

I haven't seen anything which would lead me to believe its the vent. If it was the vent, motor would run fine until it started to struggle. Then the gas cap would be opened and it would run a bit longer then the first time because there would be more air to suck out of the tank

Blowing air thru a vent line would help a weak pump by applying pressure inside the tank

All I have from my take on the issues

 

[bones774]

thank you for your help