1991 Z28 100% stock, 5-speed, 96,000 miles. Has new plugs and wires, new Bosch 19 lb. injectors, computer, fuel filter, coolant flush, oil flush, trans/clutch pulled flushed and inspected, motor pulled to replace oil pan seal, tpi unit has all new gaskets, rear end seal replaced and new gear oil put in, new VSS, newer stock exhaust, new air filters, and suspension was all gone through and greased. Last thing done was the timing was set and the spark advance. Only thing it needs is a new connection from the exhaust manifold to the downpipe as the bolt will not tighten and the car has a slight exhaust leak. It runs awesome, and is very quick, but I have noticed the rpms get sloppy at idle when its warmed up, rpms dip 2-300 and bouce back up frequently, it killed on me once. Today I was driving it and every time I put the clutch in, rpms surged up to 2,200. Car also seems to run a bit rich. It wasn't driven or started for 7 months prior to this, but now has fresh gas. Any ideas?