ok i bought my good ol 91 dx rex for 300 a while back and every since i got it running its been running way rich . and i have no clue why i had to put a new fuel pump in it and run a walbro 255 instead of oem could that be my prob. and woul a fuell pressure regulator fix it?

 

having a vaccum leak can also make the engine run rich. when a vaccum leak occurs the map sensor sees the leak as the engine being under more load than it actually is (the map sensor senses engine load), so it would dump more fuel in under false assumption of the load the engine is under. In normal operation at idle the engine will have a high amount of vaccum in the intake (throttle plate closed), and at WOT the intake vaccum will be close to atmospheric pressure(no vaccum) which is why having a leak in a vaccum line can make things run rich.. first thing i'd check is to make sure all the lines are plugged in and in good shape.

 

ight thinks its really ruff car it set in a hay feild for 5 years so yeah i sure there is a few rotted lines i will check it out thxs man

 

replace your o2 sensor.