I have a 99 jeep Grande cherokee with the 4.0 we bought it about 5 months ago and it has only ran about 2 and half if that .
It won't start it will turn over but won't connect I have pulled the codes and fixed what I can so far ( codes p0743 p0753 p0465 p1492 p1765 are the ones that are left with a check engine light and a security light on as well and now gas gauge does not work at all this happened about a week before replacing fuel pump )
I have replaced comp, battery temp sensor, fuel pump, fuel filter, water pump, radiator, heater core, cooling fan relay switch, and one of the trans shifting sensors, and the crank sensor. I need help please I for the life of me can't figure this girl out. It starts when it wants to and doesn't start when it doesn't want to and when she does run sometimes it will rough idle and shut off or high idle. The wife wants her jeep back on the road but I am now at a loss. Please any info or help will be grateful.

 

I believe most of those codes are related to the transmission and possibly EVAP as well. Some one with better knowledge will come along and chime in.
best of luck to you.

 

Those all look electrical except for maybe the first two and those might be being caused by electrical problems.
So I am just going to repeat what everybody says when you have electrical problems.
Check all the battery connections. Also any other grounds that are in the Jeep.
Locations in an XJ are well documented in the forum.
Not a clue about a WJ.
Also you are in the XJ section so you probably should post this in the WJ section.
Lots times it is one problem setting off all this stuff.
Find one thing that is wrong and it could fix some or everything.
That's what sucks about computerized cars.
IMO everything is not entwined with everything else.
Example is a misfire code. Even though my P0304 was just a spark plug when is it really ever that easy.
The underlying factor as they say.

 

Do you have any diagnostic equipment?
- Do you have a fuel pressure gauge?
- - what's your fuel pressure at with "key on"?
- - what's your fuel pressure at idle?

Do you have NOID Lights to check for injector pulse?

Do you have spark when cranking over the engine?

Why'd you replace the computer & where you'd get the computer from? What year / make / model did the computer come from?

Hows the battery? Are you working with a fully charged battery? How are the connections & grounds on the battery / engine / body? Did you only look at them or physically take the connection apart & clean up the connections?