Car has been running fine and then started getting codes 171 and 174 and a little hard to start sometimes. Short term fuel trims at an idle run around 17 to 19 and max out at 25 when getting into the throttle pretty hard. Trims used to run (when running perfect) anywhere from -4 to +6 with the long term averaging around 1.
So just checking to be sure this sounds like fuel pump before I sock money into the fuel pump. It does run fine, but its been my experience of lean codes on both banks means restriction due to fuel filter and or fuel pump getting ready to toast out.

Thanks all....

 

Fortunately, you do not need to use secondary diagnostics to determine fuel pressure problems in an X-308. Get (borrow or buy) a fuel pressure test gauge, make a long enough extension hose so that you can get from the test port on the front of the fuel rail to the windscreen, and tape the gauge to the outside of the windscreen. Go for a drive and watch the pressure Your pressure should be between 37 and 42 psi.
You did not mention the model of car, but if it is a SC model, the pressure should be about 2.5 bar above manifold pressure, which is within the above range.

 

1999 xj8l

 

32 to 35 for the first minute or two, then runs around 40 after that

 

No problem there.

 

Well, I wonder about the first minute or two, but I agree that it is likely noit the problem. But I do wonder...

Have you had a really good look at the full load breather tube, then the whole intake plenum for cracks. The Full load breather can hide a lengthwise crack pretty well, and the main plenum can develop cracks nearthe resonator.

I gotta tell you about the high fuel trim I chased for several months- It turned out to be the front main oil seal was butchered from when I reassembled the engine! After I hooked up my smoke tester,I found nothing for a minute or so, then the smoke poured from the front of the engine. And, believe it or not, no oil seemed to be leaking out there!

 

wow,, strange no oil leak! I have a homemade smoker I made with a glowplug and babyoil as the smoking agent. I will smoke the motor. Replaced the breather tube several months back. I do have the "gross leak in evap" code again, last time I had it, the main line to one of the charcoal canisters was off. The clip was broke.
Reason I was thinking pump is on American cars, I can have both bans running lean codes and still have fuel pressure but not enough volume under pressure. I change out the fuel pump and problem solved. I havent jumped in to change this one yet because its a pain with the 2 plastic gas lines coming out of the bottom. I changed this 5 years ago and kinked one of those lines and without dropping the rearend, getting to those lines is almost impossible.

Thanks for the advice. I lurk around alot and because of this forum I repaired the ABS issue I had because of the control board loosing contact with the power wire. Resoldered and all is good! Saved me big money! lol
Thanks and have a Great day!!!