I'm trying to figure out if I have a problem here, and I think I do. On cold start, my Jeep kicks up to 1000 rpms and sits there for a while. After anywhere from 3-5min of idling, it works its way back down to around 700rpm. I'm thinking this wasn't always the case...I was thinking that it would hit 1000 rpm upon startup, but then within seconds idle down to 700. Does this sound right? I've smoke tested (never completely cold, though) and checked everywhere for a vacuum leak and found nothing.
I've also cleaned the IAC with no change. I have the IAC from my old TB laying here that I may end up swapping onto it to see if it makes a difference. This TB is a used OEM one I put on about 2 years ago when my OEM one was leaking around the throttle shaft. My original IAC on my OEM TB worked fine, so I assume it would be worthwhile to swap them and see if there's any change.
Anyone else deal with this? Any other ideas? My only other thought is that maybe my intake manifold may be cracked on the bottom or something where I can't see it. The only way I could smoke test it cold would be to leave it at a buddy's shop over night and then test it the next morning, but the logistics of that make it a less than desirable option. And my least favorite thing in the world is removing/reinstalling intake and exhaust manifolds on this Jeep, so I don't want to just take them off without definitive proof if I can avoid it.
I've also cleaned the IAC with no change. I have the IAC from my old TB laying here that I may end up swapping onto it to see if it makes a difference. This TB is a used OEM one I put on about 2 years ago when my OEM one was leaking around the throttle shaft. My original IAC on my OEM TB worked fine, so I assume it would be worthwhile to swap them and see if there's any change.
Anyone else deal with this? Any other ideas? My only other thought is that maybe my intake manifold may be cracked on the bottom or something where I can't see it. The only way I could smoke test it cold would be to leave it at a buddy's shop over night and then test it the next morning, but the logistics of that make it a less than desirable option. And my least favorite thing in the world is removing/reinstalling intake and exhaust manifolds on this Jeep, so I don't want to just take them off without definitive proof if I can avoid it.
