air intake manifold leak

I have a 1989 Jeep Cherokee 4.0 std. transmission, with 4x4. The engine was crap so I pulled it out, in its place I put a 1992 Jeep 4.0. I personally did not hook all the components up like electric, intake, exhaust. So a shop put the 1989 air intake manifold on the 1992 jeep engine and hooked up the wiring. Well now the 1989 intake manifold on the 1992 engine sounds like it is leaking. I thought it might be the muffler but I think that would be more of a ticking sound or I would see movements on the tachometer at idle like the idle going up and then back down. But I do not, so when I pull the accelerator cable I hear an extra suction sound on the back of the intake manifold close to the firewall on the driver side. I was wondering if I could
just put my 1992 intake manifold on and change the throttle body for it to work, maybe change some other things as well. Or is that not possible and I have to take the intake manifold off and fix it some how??? Oh I think the fuel injection system is a little bit different from the 89 to 92 years so could that also not allow me to put the 1992 air intake manifold in the 1989 jeep b/c the electrical connections are different.