I have had a problem with the idle on my 96 Civic Hatch w/ 94 GSR motor swap w/ skunk 2 single butterfly intake manifold for along time. When I got the motor it came with an LS P75 ecu (Non-Vtec). I ended up getting 2 JDM ITR P73 OBD2 ECU's (Vtec) & they both of them give me a really messed up idle, it takes forever to keep the car running, dies while driving. But when I use the P75 OBD2 ECU (Non-Vtec) it idles perfectly. I have a P72 OBD2 ecu on the way. If this don't work, what can I do to get Vtec operational & have my car running right. What do you think could be the problem when the P75 works well but the P73 won't work? I don't know if I can use a SAFC or V-AFC to adjust fuel & timing if that would correct the problem, or if I just need to go to an OBD1 & jumper. (and if I do go with an OBD1, what ECU would work well & what cars are they from?)