Chevrolet Repair: lost, o2 sensors, sensor tps

Question
My 93 suburban has a low rpm stumble(900-1200 rpm)It also has no power pulling a hill. It loses 20 mph up a 5% 5 mile long hill. We live at 7000 ft. above sea level. It also will not pull a hill off road in low gear. It seems as you are not going to make it up the hill. If I shift transfer case to low it gets more rpm and will pull okay. I have replace the map sensor, the o2 sensor,tps sensor and iac sensor. The problem still persists.

Answer
HI BILL, SOUNDS TO ME LIKE A PARTIALLY PLUG CONVERTOR OR CONVERTORS..WHAT I WOULD DO IS REMOVE THE O2 SENSORS IN FRONT OF THE CONVERTORS BOTH BANKS. DRIVE IT LIKE THIS JUST TO SEE IF THE PROBLEM IS GONE. THIS WILL BE LOUD LIKE THIS BUT IT IS JUST A TEST TO SEE. MAKE SURE THE O2 SENSOR WIRING HARNESS IS HELD UP AWAY FROM ANY MOVING PARTS AND NOT BY THE HOT EXHAUST THAT WILL BE PRESENT..LET ME KNOW IF THIS TAKES CARE OF IT..GOOD LUCK,,, TOM..