My bother has a 01 HO, we just took it to the dealer for a new lift pump, at idle its around 12 psi. the bad part is he can pull it down under 5 psi with a stock truck. His truck seems to have as much power stock as my 2000 with with my comp on setting one. Is it using more fuel that most high outputs do, a bad fuel pump, or would it be that the diprocol gauge not working correctly. Could it be that we didnt get all the air purged out of the lines. Thanks

 

if it is a fuel pressure gauge accuracy question i would get a master gauge and use the tap on the injection pump and compare readings. my 2002 with superchips 70 hp setting i run 12 to 13 at idle and most cruise speeds. wide open i am at 9 psi. this is a original lift pump with 42,000 miles.