Weird misfire or "hesitition" after ka24de from convertible swap

[keytops]

Ok heres the stroy, I have a 91 240 coupe se model with a manual trans from the factory, I recently blew my motor (high compression head and port and polish stock internals died because a cam broke and the pistons hit the valves O_O) so I decided to go with another motor I took out of a 240 convertible a while back as it only had 35,xxx original factory miles *mwahahaha its all mine!!!* on it and swap it.

So I pulled my motor and transmission, then on the new motor I pulled off the auto flywheel and pilot busing ect. swapd the manual stuff over added new manual pilot bushing and the throttle body just to be safe (used a new gasket) then i took the intake manifold off as one peice, replaced all the coolant lines and vac lines and thed put it back together with an intake manifold spacer gasket. Then I droped the motor in.

The problem that I'm having is while the enigne is running it occationally seems like it misfires, as in its sitting there idling and at random interavals theres a little pop from the half pipe the engine idle drops momentarily and then back to running normal. It seems to drive ok pulls hard no hesitation sometimes the idle hangs out at 1200 or so and slowly drops down after pulling it out of gear. If you rev it to 2 grand or so with no load it hesitates and shakes quite a bit.

So far I have replaced the cap, rotor, plugs, and wires. cleaned the IACV and swapped it with my old one (I was having an idle problem also its fixed though) tested the car without the o2 sensor connected, with the purge line from the charcol canister plugged, with the line going to the fuel regulator pluged, checked for manifold leaks as well as vacuum leaks by spraying with wd-40 around gaskets, made sure all vacuum lines are in the right places, checked the egr, cleaned the maf, pinched the blow-by hose to see if engine idle drops, unpluged each injector to check the power balance, checked the timing and no CEL after 30 mins of driving at various speeds. Ive tried everything I can think of and what I could find in the FSM. so.....

I cant think of anything else that could be wrong, time to throw in the towel and ask for help. So help me pleeeeeeeeeeeeeeeeeeeeeeeeease!!!