Need Help!! 1988 XJ with 2.5 I4 rough idle and power loss

Hey everyone I need some help. I recently acquired a 1988 xj with the 2.5L throttle body injected 4 banger. It had the motor rebuilt before I bought it and only has 2200 miles on the rebuild. For some reason it has a hard time staying alive while idling. Some how it manages to keep running but the RPM's drop low and the motor shutters then the RPMs come back up and then it repeats. Also I have noticed while driving I can hit the throttle and get almost no response from it until the throttle is almost floored. I am thinking maybe the IAC or the O2 sensor, I also thought maybe the Cat is clogged up. If anyone has any ideas of what it may be or how to go about diagnosing this issue any input would be greatly appreciated

First place to look is at the firewall.
That braided strap needs to run from the firewall to the engine.

Second place to look is at the vacuum lines at teh intake manifold just below the throttle body.

Have the intake manifold bolts worked loose?