'88 Comanche high idle speed

[pringlechip88]

Hi i have an 88 Comanche that i just finished installing a 96 cherokee engine.

when i start it up it revs up really high and does not idle back down. i was wondering what is causing it. i think it is an oxygen sensor but i really don't know. any help is greatly appreciated. thanks in advance

[TNT]

Give us some details. Which harness are you using? And what throttle body did you use? It hard to say. Did you swap all the sensors or what did you do?

[pringlechip88]

the harness came off of my 88. the sensors came off my 88 engine. the throttle body,lifters,intake,exhaust came of the 96 engine. thats about all i really can say i guess. sorry for not having all the info :oops:

[bhorocks]

check you vacuum lines...