it bogs down then when you try to accerleate

On a 99 chevy astro van with 147,000 miles and 4. something engine I installed 2 fuel pumps, oil presser sensor, throttle positioning sensor, mass air flow sensor, and 2 fuel filters. and still having problems. No codes to be read. starts great idles great, sounds great while running and driving up to normal speed it bogs down then when you try to accerleate out of it it bogs again and gets worse and worse till your going 5mph. then restart and starts problem all over again. can even restart in nuetural and get same response. ... also after install of first fuel pump the dim lights went out but bright lights still work any ideas? inital problem was bad fuel pump. one more thing when it bogs down it backfires thru the intake too. Brad