My 98 xj has given me a lot of issues since I bought it. Driving it home it kept dying as I would slow down and come to an idle. now it won't start. I changed spark plugs, new battery, alternator, starter distributor, camshaft position sensor, crankshaft position sensor, head gasket, intake gasket, valve cover gasket, pistons, radiator, thermostat, timing chain with sprockets, serpentine belt, and ignition... it has good compression so I'm thinking its fuel related or possibly a bad ground..it turns over but won't start please help me!

 

Wow, now that is a laundry list of replacements!

Assuming all is good with those, I would clean my grounds up till they are all shiny and check the fuel pressure at the rail. If you are getting fuel, your plugs should be wet after a cranking session.
If the pressure is good, I would go back and check for spark. After shooting it with that parts cannon, I hope they are working as they should.

 

The idle air controller (IAC) would have been my first suspect for stalling when stopping. I would also test the throttle position sensor.

Did the non-start begin after replacing the distributor and camshaft and crank sensors? Bad part out of the box isn't uncommon, and an incorrectly timed distributor would also cause a no-start.

 

so the motor has good compression, but does it have correct fuel pressure and spark ?

If yes, the XJ dizzy is, by many accounts, most easy to mistakenly replace one tooth out

I would follow the fault finding procedures outlined in the free download FSM to work through these issue logically

 

The no start issue was before I replaced sensors and distributor its doing the same thing it did before I replaced everything minus occasional white smoke clouds ( it dose not smoke anymore after all engine work)

 

There is good info here for you, I don't have the time right this minute to dig through it but here are the FSM's you can use for troubleshooting.

http://www.colorado4wheel.com/manuals/Jeep/XJ/