2003 Chevy Truck 2003 Chevy S-10 Problem

I have a 4.3 liter, Auto, loosing power and knocking at a high RPM. I used a running diagnostic, showing the timing at 17 during idle. While increaseing rpm's at 2000 the engine begins to jump and miss showing 38 timing, from that point on the timing drops as rpm's increase. At 2/3rds throtle the timing is back down to 5, and engine is knocking and rpm's fall to 600, full throtle the engine will barely run. It has thrown a few codes, MAP, and TPS, and Random Misfire, I have replaced the MAF, TPS, fuel filter, and plugs, and still the same symptoms.