no 6 cylinder misfire

[swensonb71]

i have a 96 gmc z71 that idles and starts fine. as you use about 1/4 throttle or put it under a slight incline requireing more power the code for #6 cylinder code pops up and sometimes a multiple misfire code pops up if i mash the gas pedal. i noticed when i did mash the gas with my scanner hooked up that the timing woudl retard itself to accomidate fuel to rich ( i think). any ideas?

also does anyone know about a scanner that would dispaly the cam position sensor info that has the capability to reset the sensor without going to the dealership?

[LastOne]

Try swapping the spark plug and wire with 7, the wire should be close enough to reach. Also could be carbon buildup on the valves. Try some Seafoam in the intake. Suck it in via the vac hose off the brake booster.
On my 5.7 it was mechanical sticking in the heads, I switched to full synthetic oil and after about 2500 miles it was cured.