Help, no power....

[Supra chick's dad]

Hey first post here but read a bunch. I put a used Jap motor in my daughter's 89 Turbo Supra as the previous owner han the original out of oil. It all went in real well, and starts right up and idles nicely. However when you touch the gas pedal the rpm drops to 500 rpm's and wants to die. If you let up it returns to a smooth 800rpm's. Cannot possibly get it to rev at all. Here is what I've checked. MAF, TPS, O2, MAP, all connections on the engine harness for bad connections and every pin and socket behind the glove box. Here is what I have noticed, exhaust feels a bit weak at the exhaust tip. I can hold it back without any change in rpm and it doesn't seem to build up a lot of pressure. Small electrical zap when I turn off the ignition and put my hand oth the rocker panel as I get out of the car. This pulse is almost everytime.
Any ideas would be appreciated.....