Fuel issue? Advice needed.

I have a 96 model XJ. I was on my way home from a long trip Tuesday. I was was using cruise control on a flat road at 65 mph at about 2100 rpm. The engine started sputtering as though I was running out of gas (I had a half tank). I turned off cruise control and pumped the gas peddle and the vehicle started running ok. But, it would sputter intermittantly. I was able to make it to a gas station where I checked vacuum lines (they seemed ok) and topped off the gas tank. I let the engine cool down a bit before continuing on home. I was able to make it home (about 90 miles) cruising between 55 and 60 mph, but it still sputtered a little every now and then. It seemed more apparent when going up hills. The vehicle runs araound town with no problem.

I was reading the fuel pump test in my Chilton's manual. It says my fuel pressure should be 31 psi at idle. To disconnect the vacuum line to the pressure regulator and the pressure should go up to 39 psi. On my Jeep the fuel pressure regulator is part of the pump assembly and doesn't have a vacuum line to it. How do I check my fuel pump?

Do ya'll have any other ideas on what could be the cause of the trouble? I'm going to check my plugs, wires and distributor cap as well.

Thanks,

Update:

I put the pressure guage on the rail and its running 50 psi at idle. It dropped down to 48 psi after about 10 minutes and down to 26 psi after about 30 minutes. Is this pressure too high? Since the book I have has instructions for testing a different type of fuel pump assembly is the 31 -39 psi correct for mine as well?

Also, the plugs and distributor cap look a little worn but ok. I haven't ohmed out the wires yet.

Forget too high, 26 is too low. Sounds like you either have a pump going south or possibly a clogged fuel filter. A lot of crap in the tank can cause similar symptoms while it clogs the input screen.

old_man said:

Forget too high, 26 is too low. Sounds like you either have a pump going south or possibly a clogged fuel filter. A lot of crap in the tank can cause similar symptoms while it clogs the input screen.

Click to expand...

when I thought I was having problems with my CPS...its was...

1. clogged filter...
2. crap in the tank.

go with those first, and work your way up to the pump.

FWIW YMMV

There was also a bad batch of tanks from jeep, 95 or 96 I think, had a coworker at Lucent who had this problem. The tank was literally breaking down inside and the sock was getting clogged with a black tarry stuff that the winter fuel was not friendly with [alchohol additive for NJ] He went thru 3 fuel pumps in a week and his mechanic finally bought one from the local jeep dealer, his mech described the problem and Chrysler quietly shipped him a new tank, fuel pump and reimbursed him for towing and labor. Another one of those 'quiet' not a recall things...kind of like the transfer cases and differentials in the WJ in 99 and 00 when they first came out..

Ralph said:

Update:

I put the pressure guage on the rail and its running 50 psi at idle. It dropped down to 48 psi after about 10 minutes and down to 26 psi after about 30 minutes. Is this pressure too high? Since the book I have has instructions for testing a different type of fuel pump assembly is the 31 -39 psi correct for mine as well?

Also, the plugs and distributor cap look a little worn but ok. I haven't ohmed out the wires yet.

Click to expand...

After rereading the post I should have mentioned that the pressure dropped after the engine was shut down.