Hi.. Here is my prob: I swapped a 91 built motor into my 87, using all S4 sensors on the S5 parts. The engine has about 100 miles on it, and the only problem I am having is that it runs fine under light throttle in the higher gears like 3 and up. When I give it gas, it acts like it is starving for fuel, but there is black smoke coming out the exhaust so I dont think that is it. The car starts fine and has about 120 psi on all sides, and it will accelerate fine in the lower gears. If it starts to miss and I let the engine idle for 2 seconds, the miss dissappears and it is fine until I floor it again. Thanks!

 

which injectors are you using?

 

87 injectors, 89 fuel rails, all new seals. The thing that gets me is that the computer kicks into some mode when i am trying to accelerate that causes a miss, and then when I release the gas pedal, it will miss for about two seconds before changing modes back to normal and the miss goes away. Wierd!

 

that is weird