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88 chevy pickup 5.7 high idle some stalling when put in drive or reverse gears. checked for vacum leaks around tbi base gaskets and throttle shaft, EGR, intake gaskets and all hoses. all checked out good. checked timing with light that was good. started cleaning all grounds in the engine compartment, no luck. tested iac and cleaned it still no luck. I was stumped but was drawn back to timing and the distributor because of the stalling when put into gear and a load was applied to the engine. I took the cap off the distributor and by hand rolled the engine back and forth while watching the rotor to check for play in timing chain, there was little slack. I decided to pull the ditributor and by hand turned the gear and watched the rotor, it had a sticky spot when rotating. HHHMMMM I tested the pickup, that was good. I decided to put a spare distributor back in place of the old, problem solved. I determined later it was the star wheel in the distributor that the pickup coil senses when to fire each cylinder. the star wheel must break down, and seemed to have a small fracture crack???? but that was the root of all my headaches. hope this is helpful to someone