Angelov71

Gents, I need some opinions/suggestions...So here is the problem...I am cruising at nice speed say 45-55mph and when I floored the gass pedal the tranny downshifts to 2nd gear but the engine starts spotting, like loosing power or asking for gas. I parked the car and check the fuel pressure at idle, when cold is good 6-7psi when fully hot it drops to 3psi maybe 3.5psi, it is a new pump from Kanter, this one has no return line but my old one did, so i left the return hose open with a mess like filter at the tip to prevent dirt. Last note, the gas tank has a "vent hose" that runs from the top of the tank along the side of the filler neck, originally it had a "filter like" but it was old/rusted and I threw it away, could this missing filter be the cause of loosing fuel pressure? By the way my gas tank cap says " not vented" Can anyone school me on what does this means? Any help is greatly appreciated. Let me know if you need more info!

Angelo