Went to Chev Dealer. Said a have a Internal Optic spark problem which means they said I need a DISTRIBUTOR which will cost $1100.00 for parts and labor. ????

My 94 LT 1 with 104,000 miles is giving me a IDLE spike when stop but still in gear. Only does it after the engine has warmed up. No problems while driving or accelerating. Does spike a little when in parked but not all the time. It never stalls. Just a major spike from 1 to 2 rpms when stopped and in gear. NO codes come up. Replaced MAF, MAP and upstream O2 sensors. Distributor? just wires or plugs? Is Chev right? Any ideas ...Thanks