Ok guys, I need some help. My GC is a 2004, 4.0 with 160000 miles. In the last month it has gotten a little hard to start at times. Cycle the key on and off and it seems to help. I had three codes on it, p0300-p0301-p0303. I replaced spark plugs and cleared the codes, ran fine and no more codes. Today I ran it again and it started getting a little hesitation in the pedal. Then I noticed when I brake or turn it seems to run worse for a little while then it gets better. I'm thinking trash in the tank. I brought it home and let it idle and man it started running really bad. I scanned it again and I'm getting the p0174 engine running lean. So I think fuel pump, regulator or screen stopped up. But I've read all kinds of things on line and now I'm not as sure. I really don't want to waste a bunch of money throwing parts at it. Oh, and when I shut it off I hear a gurgling sound in the tank. Any help you can offer would be great. Thanks

 

I think you're on the right track in suspecting the fuel pump. Check the pressure and let it sit for a while, the pump should hold pressure, if it drops you have a bad check valve.

 

I was gonna check the pressure but I don't see anywhere on the rack to check it. And do you think the check valve would make it run rough ?

 

No, it will make for an excessive crank time. There should be a test port on the fuel rail.

 

I'll look again

 

This thing has no return on the rack, from what I have read it is on the fuel filter. I pulled the line on the rack and it pumps for a second and shuts off. It never made any pressure, I even turned the key on and off several times. I am getting fuel to the gauge but it never moved. I think I'm gonna take the supply line off of the filter and check the pressure there.

 

I have no return line too, but there is, or should be a test port on the rail at about #3 injector.