i checked my fuel pressure for the first time today, it was right about 40 initially, i messed around with it a bit, and set it to about 47 or 48. all you do for this is put the pressure tester in the port, and turn the key right? so anyhow i get it set and it holds steady after it goes to 48, doesnt drop or anything. then i start the car and it goes crazy, flips back and forth really fast almost from one extreme to the other. whats the deal? i thought it was supposed to stay steady with the engine running?

 

It IS supposed to stay steady... Actually when you SET the fuel pressure, youre generally supposed to set it with the engine running, and the vacuum line to the regulator disconnected and plugged, that way the pressure reading doesnt fluctuate. This is basically giving you your WOT fuel pressure reading and you adjust based on that.

I don't know why yours is bouncing like that....I've never heard of that before.

 

i think i have a minor vacuum leak, doesnt want to idle low, i keep it set at about 800 and it only idles steady about half the time, rest of the time it jumps from 600-1000 and will die sometimes if im sitting stopped in gear with the brake on. it will idle steady if i set it to 9 or 1k but i like the lower exhaust tone lol. if i spray carb cleaner around the intake manifold area it will sputter and almost die. could a vacuum leak cause that the pressure to jump like that?

 

do you mean plugging the vacuum line itself, or on the regulator where it plugs into?