I swapd in a 98ex engine into a 92hatch runs great no cel lights nothing...but now when you get onto the highway for about 10mins its starts to miss bad but no cel lights or anything but if you shut off the car and then start it up it goes away for another 10mins so i replace plugs and wires think that but it only lasted acouple days and started doing it again...

 

what ecu are you running? did you use the obd2 to obd1 jumper harness?

 

bump