i have a 1990 chevrolet suburban thatbogs down when i give it gas, have changed fuel pump. fuel filter, set timing , plug wires , drained fuel tank, changed injectors , changed coil , it starts and idles fine.

Need to verify that TPS and MAP are working properly. How is the compression?

//2000CAYukon

Could also be a restricted exhaust. If you remove the O2 sensor and drive it does the problem go away?

//2000CAYukon

Had very similar situation on my '90 Suburban 454. Mechanic found that the distributor shaft journal bearings were shot. Put in a whole new distributor assy from GM (about $250), and suddenly had all the power I forgot I origanially had.

Good luck, Steve