When I sometimes go to start my '00 xj, I will put the key in, let it prime for a few seconds and go to start it and it will turn over as long as I want without firing. Turn it off and immediately start without priming and it fires quickly. When it does that I have a couple related issues. Failure to lock up the torque converter and it drives like *** like it has no power. I have replaced all the solenoids and replaced the wiring in the transmission. Otherwise it literally fires immediately and drives fine, and locks up tcc. It baffles me.

I am wondering if I have a problem with either the pcm, a ground or a sensor issue as I know the pcm orders lock up at temp in 3rd gear. Input and output speed sensors on aw4?

'00 xj 5.5 long arm, 37s, waggy 44s locked, geared, trussed front and rear.

 

The starting issue sounds like a fuel pump starting to go

 

Agreed, get a pressure tester and hook it to the Shraeder valve on the rail. It sounds like the check valve has given out and gas is draining out of the lines. Running poor could be a result of low pressure as well.

 

^^^^^^^X3

 

So I called a transmission shop and it looks like there is at least one confirmed problem and a secondary symptom. After shutting off and heat soaking, (the exhaust pipe rubs against oil pqn and transmission) the transmission is using the heat temp and picking the lockup inhibited mode. The other issue looks to be a clogged cat and third, I have a fuel pressure tester and I'll look into it. Apparently on the later models, fuel is supposed to eventually drain back and go down to 0psi. (According to the FSM.)

 

And thanks to to all.

 

I had the same issue, the check valve in my fuel pump failed. i installed a new fuel pump and the problem has gone away completely. an easy way to check it is let the truck sit a few minutes and then go push the schraeder valve down carefully with a screw driver or something, you should get some fuel to spray out of it.