87 sunbird rough idle still

Got an 87 sunbird, engine almost all redone, but still rough idle as well as rough upon gentle acceleration. But when you hit it it flies (it is a manual, NOT an automatic). New ECU, fuel injector, AIC valve, head gasket and set, checked hoses for vacuum leak, The EGR, when connected causes car to run and idle WORSE than when disconnected, so I blocked it off with no pinging, or other bad signs. What is it??? Tech at Haynes said it can't be ignition since it accelerated vigorously when floored and at high rpm's, got to be vacuum. But found no vacuum leak so far.Anyone know? or am I the only one left in US with an 87 sunbird that otherwise still runs well?

Bad Throttle Position Switch? Loose or leaking Intake gasket or Throttle Body gasket? You can check for vacuum leaks with a propane wand, or by listening through a length of hose.