Really High Idle After Exhaust Manifold Replacement
 

Hi guys, I'm new here but desperately need help.

I'm getting a new to me car soon and need to get my girlfriends 1999 jeep cherokee out of the garage. The initial problem with the car was that it had an exhaust leak and her dad had a used exhaust manifold laying around but didn't have time to do it so i tried to take on the task. I made sure when i stalled the good one, it was seated correctly but when I started the car, it was idling really high. I'm not sure how high (maybe 2500-3000) because this one does not have a tachometer. Cleaned the throttle body and had no luck. I don't think it could be any of the sensors because it was fine before i took it apart.

Something I noticed though was if i tap on the throttle, the rpm's would shoot up and stay there and the gas pedal is super loose (i could put my foot under it and lift it up a few inches) but the way it rests, the throttle plate is closed. Does anyone have any input on this issue? Do you think its a mechanical issue like a vacuum leak or an electrical issue?

Odds are you broke off a vacuum line or forgot to re install it. The most likely place I can think of is the barbs on the intake manifold. Some should just have a rubber cap on them I believe two have lines connected to them. One for brakes and one for everything else.

Would you be able to take a picture for me? I forgot to label those and may have it wrong. I have a line on all three of the ports.