1989 780

I am having a issue where when under medium boost i get a slipping type motion out of the car. i originally thought maybe it was a fuel delivery issue or turbo but no luck there. Basicly ( downhill any slope 1 degree or 12 degree ) under hard boost you can feel this slip like there isnt enough fuel, car kinda bucks lightly, now uphill same thing but happens at medium boost or higher car just doesnt want to keep going it will if you push the pedal harder and the turbo is assisting more at this point. here is what has been done to the car since i have owned it i do not know its history. IRS Rear End Converted To Shocks via IPD conversion kit. No Smoke From Rear. Tach Holds Steady During Issue. Express Yourself Here Im Getting Ticked I Cant Get This Car Perfect!!!
Bad Rear End? Bad Tranny? Turbo Hoses ( Seem Solid )? anything. See Below For Item's Tried Or Replaced!

Known Issues

ABS In Failure Mode

Tried / Replaced Items

1993 B230FT Rebuilt Long Block
Rebuilt Turbo ( Very small crack near wastegate accoring to rebuilder )
New Fuel Pump
New Fuel Filter
New ECT
Used Injector's and Rail
All Vac Hoses Replaced
Resealed With Bushing Tranny ( Not Rebuilt )
New Center Support Bearing
New Engine Mounts And Tranny Mount
Used AMM
Cleaned IAC But Very Old
100Amp Alternator With New Bearings
New Harmonic Balancer
New Water Pump
New Thermostat
New Cap And Rotor ( Dist Original With Unbroken Plug In Rear Did Not Have Much Play)
Catty Was replced with Aftermarket prior to my purchase ( Its small )
New Oil Pressure Sendor