1998 Surges

MY 1998 4.3 sonoma surges on acceleration and loss of power when going up hills, when cruise is set it also surges, when I give it to much gas rpm increase but will not shift or pick up speed. had 3 codes cat system efficiency below threshold(bank 1), mass or volume circuit range performance problem, and intake air temp circuit high input. replaced plugs , cap, rotor, pvc, air filter, mass air flow sensor, also done a visual on air intake duct. also engine light was on. cleared codes, ran for several days no new codes but still runs same. anyone have any ideas that I can check out before I go and spend to much money at the shop. (please help). :confused: (truck has 103,000 miles, mostly interstate miles)

oh, I also replaced fuel filter 100 miles ago.

Have the codes checked again.

Not all codes set a check engine light.

Was the O2 code for bank 1 sensor 1?

Have the codes checked again.

Not all codes set a check engine light.

Was the O2 code for bank 1 sensor 1?




THANKS FOR REPLY, SAME CODE CAME UP AGAIN CAT SYSTEM, SO I TOOK A CHANCE AND TOOK EXHAUST APART AND FOUND CAT WAS HALF PLUGED, CLEANED OUT AND RUNS GREAT.