new tranny and wont down shift in overdrive. 94 accord lx

my 94 accord lx just received a replacement motor and tranny from jdm auto.its from a 95 odyssey. I had to swap throttle bodies, distributor... from the old one cuz the new one didn't have cruise control components, external coil... Now its seems rather gutless and it wont down shift when in d4 or d3 unless I come to complete stop, but sometimes it stays in 4th which sucks at an intersection! Also the shifter moves freely from first to neutral without pressing the button. and of course check engine light is on constantly. I've played with tranny cables fuses are good, reset ecu, fluid is new... every thing seems fine and the tranny that we took out down shifted fine so I must be missing something simple. timing? any ideas?

Get a fuel pressure gauge. You can rent one from an auto parts store. Put the gauge on the schrader fitting at the end of the fuel rail and start the car. Watch the gauge and after it is warmed up shut the car off. Watch the pressure, if it drops rapidly then there is a leak in the system. Another way which is not recommended is to remove the plugs and see if one is wet. I don't recommend this when the engine is hot a you may strip the threads but it is an option.

Thanks for the reply. It seems to have steady fuel pressure. I just pulled the code and its reading a problem with the tps. I'm getting a new one tomorrow and need to adjust. Hopefully that will resolve its inability to automatically downshift so I've been told. How ever I don't think it will resolve the loose shifter issue though. Again if I 'm in first I can freely slide the shifter all the way up to neutral. but while I'm driving in d4 the shifter will only slide freely from d3 to neutral and won't lock in position. which is a pain because sometimes I don't line up perfectly with d4 and it will slip to neutral. Linkage has been checked and is ok so I'm beginning to think someone reefed on the shifter and damaged it somehow???

I've discovered that we installed TPS wrong so now she kicks down. but now the throttle fluctuates 1 to 200 rpm when I let go of throttle cruising around 50 - 60 k. Also, the tranny hesitates, and revs increase 200rpm for about 1 second before hammering agressivly into 4th gear. I've been chasing this for weeks now until I unplugged the new ntk o2 sensor from napa which was installed with new engine, and all the issues cleared up. Why??? It runs better than ever now, but the check eng. light is on now. Should I bother trying different sensors and waste even more $$$? or how can I over ride the c.e.l.? and make it go away? Or maybe this scenario is a symptom of a whole other issue?