87 7MGTE running awful!

[Travdub666]

Ok so I bought my supra 3 years ago it was just a rolling chasis with a donner car. I did a motor swap put in a 5 speed trans with a stage 3 clutch and threw in some interior. I drove it last year when all of a sudden it quit running and wouldn't start up again. Well I figured out that it was the timing pulley it was never tight ( not my fault but I should have checked it.) 1st-3rd gear the car runs pretty decent but 4th and 5th seem like it's has no power and I can just hear my bov sound like it's open all the way. Driving it yesterday it was skipping and bucking like crazy. Any help would be great I'm kinda at a stand still. Another thing is when I fixed the timing I put it at top dead center but I think it's supposed to be 12 deg ahead? Would this make the problem? PLEASE HELP!