Alright, just did a 3.4 swap to 3.4 swap. Its 96-98 engine, I found this out due to the thicker engine mounts.

Engine has 70k on it. Runs really good, but rough at idle. Doesn't like to be floored in neutral, it kind of spits for a second and then revs up.

Pulled the codes, P-0171 (System to lean, bank 1) P-0120 (Throttle position Sensor) and a second P-0170.

*I will add I used the harness that came with the truck, not the harness on the motor I bought and I have 1 two prong connectors at the front left of my timing cover, and 1 one prong connector in the same spot with nothing that I can find goes to. Can't figure out where it went on the other engine either. I'm kind of stumped on that one.*

Anyway, I swapped out the TPS sensor from the other engine, it looks new so I tried it. Cranked right up, seemed to run just about the same with no change.

I am 98 % I've got every vacuum line perfect and no leaks. I'm good on my connectors (except those random 2). It runs 80 down the highway, no stalls, but REALLY doesn't like to be low on gas. Acts like its got crap in the tank.

Its getting like 45 miles per quarter tank currently. It also has a minor exhaust leak, I can barely hear it but no smoke, or smell that I can tell.


Any help with this would be great. I really need this in perfect running shape with decent mpg so I can start taking it to my new job next week and I won't have time to keep screwing with it. Planning on Sea-Foaming it today and changing the plugs this weekend but stumped on the other issues.


*Posting this on TR4.org as well.**