I have a jeep grand cherokee 1998. I travelled and the veheicle was parked in a garage for about a year without running. Now it cant start. A mechanic changed the computer, and did some other work, but it starts and then shuts of. One mechanic suggested that the engine might be locked or i need to change the oil and spark plugs. Any suggestions as to what might be happening.  

If it starts and shuts off, it wouldnt be locked. Did the mechanic check your fuel pump? Is there a check engine light?  

Fuel sitting around a year is not good. Fuel can start to go bad after only 3 months. Drain the tank and put in some fresh fuel.

Also, bleed it out of the fuel rails.  

he did not check the fuel pump and there is no check engine sign  

ok thank you