89 k5 blaz 5.7 backfire

89 k5 blaz 5.7 backfires out exhaust (i think) I did plugs wires cap rotor and fuel pump to no avail. the only code i get is 45 rich running. (so could it be running lean and the cpu is making it rich? It idles fine but when going down the road and i punch it ...it falls on its face and pops hesitates and backfires... I will check timing tonight as soon as i find the est wire which i hear is under the glovebox? Anyone have this problem and fixed it. Im thinking of cutting exhaust off and driving to see if it helps.

timing was off a hair EST wire was by brake booster for all to know (not glove box) 0 deg