My 1999 isuzu trooper i just bought developed a knocking noise a few days after i got it - Mechanics said it would probably cost more to rebuild than to buy a used engine. My trooper is 5spd with the 3.5L with X as the vin... Anyone know what years interchange ? I have heard that 98-01 interchange , but the mechanics said only 98-99 interchange... I NEED HELP knowing which is true and also finding a good engine!!! ANY HELP IS GREATLY APPRECIATED!!!