I have an 87 TII and just swapped the motor out of the other one I have cause new motor has blown rotor seal so it was making it overheat all the time, got motors swapped out and new motor fired first try but it has a weird idle and no vac leaks as far as i could tell. Throttle is also very weird and if i try and keep it at 2500 rpm or so it will ramdomly jump either up to 3900+ or drop down below 1200.

New plugs and upper intake and manifold is from the motor that is bad so my TPS and everything is the same as it was before.

Any ideas? Bad ground somewhere?