99 GC, no start, help please

OK, first I have to say i'm new to the forum and that i'm a foreigner (sorry for grammar:).

I have a 99 GC Laredo, 86k miles, and this saturday it quit completely...
How it started? 2 weeks ago I drove it for 5 min, turned off, filled tank, tried to start - cranks but doesn't start. OBDII gave me code P0320:
( "No Crank Reference Signal at PCM; No reference signal (crankshaft position sensor) detected during engine cranking.")

I've been reading forums earlier, and've heard about problems with cable wirings, so I made sure every connector is tight under the hood, moved every cable I saw. Then I started it- Vrooooom.
Same thing happened one week ago -5 min drive, 5 min stop (no gas this time), no start, played with cables - Vroooom...
This saturday my wife stoped to get some grociery, when wanted to start again - it started twice and quikly stalled both times. Becouse it was very low on gas, we thought it just run out. But after putting 2 gallons of gas it again cranked but didn't start.
I took it to mechanic today and he said it doesn't have to be Crank shaft sensor thats messed up, and I'm getting this code only becouse it's not starting.
Is he right? Any idea what could it be? When i turn ignition on, check engine light doesn't stay on. Fuel pump? But then it never happened during driving, only when starting....
Please help, I NEED to go on a 800 miles trip this saturday.....!!!!

Thanx a lot
sobdziad@hotmail.com

PS. I don't know if it has something to do with it, but 2 months ago I had Automatic shutdown relay changed - again no start (excactly same thing happened, but OBDII showed ASD was bad)

Oh, yeh, I forgot, its a 4.0 engine

well I don't think the stalling immediately after starting has to do with the CPS but the stalling and not starting could deffinaely caused by the CPS beign bad.

the start then stall - sounds like a bad Idle Air Control valve problem.

Well,start and stall happened only once. Right now I it only cranks and thats it.
Why is it giving CKS sensor then?

it is giving the Crankshaft Position sensor code b/c it is not getting a signal from the CPS check the connection to the CPS. it is most likely disconnected, if the connection is fine then u will need to replace the CPS.

if u need info on the location of the CPS let email me Joe dksob81@hotmail.com

make sure u check the wires coming from and going to the CPS and make sure they are not bare or cut.

I just talked to the mechanic. He said that after he looked at the fuel pump and played around with it the car started and starts all the time now. He claims it might run for another year or quit tomorrow. Is he right (to be honest, i don't know him at all) ???

He said I would need a new fuel pump assembly. Any recomendetions where to buy it from and what brand?

Thanx

humm it is possible that it is a wiring problem with the Fuel pump assebly, to be honest I would go to the dealer and get one (you can be pretty sure it will last awhile, some product from autozone are refurbished and don't last as long as they should, altho most of their parts have a Lifetime warrantee, but it's just a hassell of it always going bad.)

If you want the complete Assembly go to e-bay right around 200. Or if you want just the pump go to napa ,autozone, advanced. If he moved the wirring on the Jeep there might be a break in the wirring, had this happen to me on another Vechile car would quit acted like the fuel pump replaced it happened again no fuel pressure. Turned the key on and wiggled the wirring and the fuel pump comes on. I dont know if he moved the wires or smacked the fuel tank and the pump came on. Either way you need to check it only will go bad again.