onehightoyota
+1y
get a rebuilt motor. if you try to swap them, you'll have to swap the motor, transmission, entire fuel system, and the entire wiring harness and ecm. now thats not half the problem, making your old a/c and heat controls work with the new wiring is gonna be a pain. and makin your old instrument cluster work with all the new wiring = major pain in the ass. most likely you wont even be able to complete the swap. once you get halfway into it and realize the nightmare the wiring is going to be... you'll give up. there will be some extensive modifications that need to be made. 1'st is motor mounts, you'll need to build a set of those, then a transmission crossmember because the 2.4's tranny is longer than an old 91's. so a new tranny x-member and then a new driveshaft will need to be made, then you're gonna have to figure out how to make the new sending unit out of that 99 work in that 91's gas tank. and then you're gonna need to make sure you wire up all the vacuum sensors on the fuel system out of the 99. without them, it wont even run. the reason you gotta swap trannys too is cause the old style 91 tranny is cable driven, the 99 is all electric. and back to the instrument cluster, the iinstrument cluster in a 91 is all cable driven for the speed-o and the odometer. you'll never get those to work once you swap in the 99's motor and tranny and ecm. even if you do get that far, you'll need a custom radiator built since the necks are on opposite sides in those two trucks. and if you get that far, you'll need to start worryin with the wiring. you might as well forget it pal. buy a re-built 3.0. it'll last a long time. be a whole lot less headache.