ok i have a 96 civic hatch that ever sence i had it was verry lacking in power even for a stock civic, i thought maybe the engine was tired so i took an engine out of my project car and put in the other. when it was on the old car it would fly, now it is working like shit again. changed the cat, the exhaust and everything. fuel filter and went as far as to change the engine harness. i gave up on that and built a y8 with a set of high comp pistons. thinking this would solve my problem. car starts off strong through first and second gear but suck holes after that. in third right to the rug it wont eaven brake the 145km mark. also any slight grade of a hill you have to drop back to 4th or 3rd just to maintain speed. also i might get 350 to 400 km to a tank of gas. i have new 02 sensors and eaven went to obd1 to compensate for my check engine lights. any ideas?