I bought a 1991 XJ recently and the guy I bought it from said it need a new fuel pump. well it'll cutt in and out while its warming up. after driving for 20 mins it wont do it again. well he gave me a new fuel pump to put in it. I put it in and it still does it. I bought a new fuel pump relay and it still does it. Could it be a short somewhere? has anyone elses done this?
Michael

 

what about fuel filter?they get niglected

 

I changed it with the pump.

 

do you got a cel

 

I do not. Im gonna check to see if the bulb is good tomorrow. Lol

 

Bulb is good. and there is NO CEL.

 

O2 sensor.

I have a 91 and it did the same thing. I threw parts at it, ignoring this board.

The 02 sensor fixed it immediately. No CEL

 

Now that I think about it. I don't have one after my cat. It didnt have a o2 plug in the pipe after the cat (bought it with no muffs) but right now it doesn't have a cat (I know it's against the rules to have that but thats the way it is right now.)

 

my 99 was straight piped and it threw an o2 code but it didnt affect the idling or anything else. (Im sorry moderators for saying it was straight piped.)