Ran a fuel pressure test on my 98 Sport with the V6 sohc yesterday and came up with some interesting numbers. With the key in the on position and engine off the PSI was at 12. When the engine was cranked over PSI went up to 28 and held steady when reved to 2500rpm.

I do not know what the correct pressure is but I was told it is around 40psi without a vacuum line connected. I did the test using the schrader valve and a fuel pressure gauge I bought.

I ran the test because I thought my truck was bogging under brisk acceleration i.e. past half pedal. Turns out that it is running lean instead. The line should be clear and the fuel filter is changed on a regular basis. The engine has 136k mi on it and I like to go fast, so the fuel pump really gets a workout.

I am thinking it is either the fuel pump or the FPR. Strange though I thought an electric fuel pump just died all of a sudden. I did not think it could operated at reduced performance.

any help would be appreciated.

 

at 136, either couldbe bad. It sounds like the regulator to me, and if I'm wrong then at least you didn't have to drop a whole tank of gas. I think that the pump can run at diminished capacity though. It has to do with the bearings and such starting to bind. The motor can only impart so much force, the more drag on that motor, the less fuel you're going to get.

 

Thanks Amish.. As I said I have been a bit brutal to the fuel pump. Lots of hard acceleration and refilling the tank when it has about 1/2 gallon of gas left in it. I even ran out of gas twice going to the gas station. Man those 4.10 gears are not forgiving. So if it is the pump it has every right to be on its way out.