Have a 91 f150 with a 300 that runs rich. it runs rough/hesitates, idles rough/won't idle. I created a vacuum Leak by pulling a vacuum line off and that makes it run pretty good. replaced MAP and temp censors. Also it shifts hard, and pulling vac line off helped with that as well

 

Did you check codes?

 

I haven't but the check engine light is not on

 

Check fuel psi.

Remove vacuum line from fuel pressure regulator and see if fuel is visible. If the diaphragm is ruptured, then it would pull fuel into the intake.

 

Pull codes and measure fuel, post up the results you get.

 

Replaced fuel pump recently didn't change anything, have checked pressure regulator already, I'll pull the codes on Monday I'm at my in-laws for the weekend