My son and I are building a 91 Cherokee. We just swapped a 94 I6 HO into a 91 .... it starts and idles fine, runs smooth to 2500 RPM even under load. Then begins to miss and barely rev to 3000. New exhaust incl. CAT, new dist cap and Rotor, new plugs. Swapped: plug wires, Injector rail and injectors, throttle body, coil, computer (these all came from some doner cherokees we have for parts) The 94 was coupled to a manual but we are using the auto from the 91 so we are using the 91 flywheel and 91 crank sensor. I really need to get this running for my son .... HELP I'm going nuts.

 

Hi and welcome from Tj in NJ. I would check the TPS (throttle position sensor) and see if that's it. My son in law had a similar problem and that's what it turned out to be...Tj

 

Tj,
Thanks for the reply ..... I'll check the TPS .. I'll report back.

EJ

 

Sorry about the long delay ... but I thought I should get back with what the issue turned out to be. Ended up the Crankshaft position sensor was loose! We tightened it up and the engine ran excellent. We actually did drop one of the bolts into the bell housing ... we fished it out with a magnet. Anyway .... it now runs great!

EJ