89XJDan

I've had my XJ for about three and a half weeks now. Never had at real problems with it except for the brakes which are on the agenda. The idle was a little rough, but I wouldn't call it bad for an old Jeep in a hot summer.

Rewind to Tuesday:
Spent some time working with the radio, getting fed up and leaving without one, wires loose. And headed for a friend's house. About a mile from home it stalls out. It will turn, and start, but won't stay running. And I'm stuck on the side of the highway with too much common sense to try to fix it then and there. After a tow home it gets dropped off in front of the neighbors house. Still will start and immediately die. Pop the hood, open and close the throttle a couple times and BAM! Fires up without a problem and I drive it into the driveway, let it run for a while, and it doesn't die. Turn it off, let it sit for a while, then try again. And it still fires right up and runs without a problem. Goose the throttle a few times, runs without a problem. But don't wanna push it so I take the Cobalt over there.

Come back later that night and will start but won't stay running again. Play with the throttle again but this time it won't stay running. Frustrated from the day of problems with the thing and go inside for the night.

Wednesday: Took the Cobalt to work, and thought up every possible thing it could be, and why I think that's the culprit. But still too frustrated with a crappy weekend(my weekends are Mondays and Tuesdays.) And take a day to calm don't so I don't get pissed off and break stuff. Tried throttle body cleaner, for a good long time, then let it sit overnight.

Thursday: Have the motivation, and energy to get something done. Pick up a fuel filter with the hopes that it takes care of it, and is the cheapest fix. Garage key up and walked away and doesn't get home until after dark. Well there goes that. Will start but not stay running again.

Today: Work sucked, problems with poor diagrams in my Chilton manuals, and missing parts in the Jeep itself. Couldn't bring myself to do it. Instead I go inside and watch my Twins lose a painful loss.

I need help narrowing down what this could be. My list so far is:
Fuel filter(fingers crossed)
Fuel pump(don't think so because failure should be immediate, not sporadic as far as I know)
Throttle position sensor?
MAP sensor?
FPR?
And from left field: Could my wiring mess with the radio possibly trigger some sort of security system? Thinking someone is trying to hotwire the vehicle thus shutting itself down?

If I missed something or wasn't specific enough, let me know and I'll try to be as exact as possible.

Slick761

My fuel pump went intermittent.... You should probably hook a pressure test up to the fuel rail but that really sounds like a fuel pump to me. Mine did almost the exact same thing.

89XJDan

My fuel rail doesn't have a test cap. :/

Slick761

What do you mean? No cap on the schraeder valve?

89XJDan

I don't think I even have the valve. There's nothing behind my air intake elbow. Nowhere to relieve fuel pressure.

Slick761

Here it is buddy. Should be a hex cap on it. It's jury like a valve stem on your tire. Just behind the pressure regulator. If you turn our key and prime the pump then hit this valve it should SPRAY fuel.

Slick761

Oops... here