i bet Les Meyer or Captain hook have seen this. i have been experiencing an ever worsening buck surge stumble. it sometimes is violent enough to drop rpm way down ans speedometer drops to below actual speed. sometimes it will ever so briefly flicker a brake lamp or abs lamp or battery lamp. no trouble codes are stored Blazer is a fine running 270k mile blazer. Les Meyer helped me repair p0300 by adjusting cps, it is now about -1degree. today it bucked and spit a code while i had code reader attached. i will attach pictures. odd thing i see is rpm = 7500 tps is 0.0%.. speed may be right.
previously while it was bucking i was watching B1 02, it would show .9 volts (rich) right after the buck then go back to normal.
for a different reason i just replaced fuel pump pressure is now good.
you insight will be greatly appreciated,
thanks in advance.
Marty.