my 97' 4.2L V6 has had a missing issue for a few months now, changing out sparkplugs fixed it for aqile but it came back. I finaly broke down and bought a fuel pressure gauge and checked the fuel pressure. With the truck off and pump off the pressure in teh line is 41psi, right where it shoud be (according to the repair manual). with the truck on its only at 30-31psi, the manual says it should be 35-40psi. is this right? Im assuming if it is the regulators gone bad, but dont want to replace it until I get a secound oppinion. Thanks for the help.

 

did you take the vaccum line off when the truck was running?

 

not yet, that was my next corse of action