97 Chevy pickup 4.3 with P0300 code

I have a 97 chevy Cheyene pickup with a 4.3, automatic. It has 109,000 miles on it, and has been a very dependable vehicle. But lately has been having check engine come on it the engine is being pulled down like when going up a grade. When it does this the engine runs rough and the check engine flashes. It eventually stops flashing and stays on solid. I have had this problem off and on for quite some time, but have never been able to chase down the problem. It is now happening more often, so I broke down and purchased a code reader. The code reader one time gave me the code p0304, but now is just p0300. I checked for loose plug wires but did not find anything loose. I would appreciate any help that you can give me. I have had this vehicle to the shop for it, but by then the code has cleared, and the check engine has went out. Here is the data from the live data stream from the code reader when it started to give the error, and the error code stored, and pending: Control Module $10 SAE J1850 VPW Pending Codes P0300 Random / Multiple Cylinder Misfire Detected Control Module $10 SAE J1850 VPW Stored Codes P0300 Random / Multiple Cylinder Misfire Detected DTC_CNT 0 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 11.4 ETC(°F) 167 SHRTFT1(%) 5.5 LONGFT1(%) 10.9 SHRTFT2(%) 0.8 LONGFT2(%) 4.7 MAP(inHg) 20.7 RPM(/min) 1678 VSS(mph) 50 SPARKADV(°) 32 IAT(°F) 37 MAF(lb/min) 4.094 TP(%) 16.5 O2S B1S123-B2S1--- O2B1S1(V) 0.040 SHRTFTB1S1(%) 2.3 O2B1S2(V) 0.790 O2B1S3(V) 0.805 O2B2S1(V) 0.435 SHRTFTB2S1(%) 8.6 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 14.9 ETC(°F) 167 SHRTFT1(%) 2.3 LONGFT1(%) 10.9 SHRTFT2(%) 8.6 LONGFT2(%) 5.5 MAP(inHg) 20.7 RPM(/min) 1661 VSS(mph) 49 SPARKADV(°) 32 IAT(°F) 37 MAF(lb/min) 3.792 TP(%) 14.5 O2S B1S123-B2S1--- O2B1S1(V) 0.070 SHRTFTB1S1(%) 2.3 O2B1S2(V) 0.080 O2B1S3(V) 0.810 O2B2S1(V) 0.135 SHRTFTB2S1(%) 10.2 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 10.6 ETC(°F) 167 SHRTFT1(%) 4.7 LONGFT1(%) 11.7 SHRTFT2(%) 10.2 LONGFT2(%) 7.8 MAP(inHg) 16.8 RPM(/min) 1571 VSS(mph) 49 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 2.915 TP(%) 8.2 O2S B1S123-B2S1--- O2B1S1(V) 0.085 SHRTFTB1S1(%) 5.5 O2B1S2(V) 0.055 O2B1S3(V) 0.815 O2B2S1(V) 0.130 SHRTFTB2S1(%) 12.5 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 11.8 ETC(°F) 167 SHRTFT1(%) 6.3 LONGFT1(%) 13.3 SHRTFT2(%) 10.9 LONGFT2(%) 10.2 MAP(inHg) 17.4 RPM(/min) 1587 VSS(mph) 48 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 3.214 TP(%) 9.0 O2S B1S123-B2S1--- O2B1S1(V) 0.480 SHRTFTB1S1(%) 5.5 O2B1S2(V) 0.050 O2B1S3(V) 0.800 O2B2S1(V) 0.845 SHRTFTB2S1(%) 7.8 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 12.9 ETC(°F) 167 SHRTFT1(%) 3.1 LONGFT1(%) 14.1 SHRTFT2(%) 5.5 LONGFT2(%) 10.9 MAP(inHg) 17.7 RPM(/min) 1645 VSS(mph) 48 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 3.491 TP(%) 10.2 O2S B1S123-B2S1--- O2B1S1(V) 0.425 SHRTFTB1S1(%) -1.6 O2B1S2(V) 0.340 O2B1S3(V) 0.785 O2B2S1(V) 0.855 SHRTFTB2S1(%) 2.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 14.9 ETC(°F) 167 SHRTFT1(%) -4.7 LONGFT1(%) 14.1 SHRTFT2(%) 0.0 LONGFT2(%) 11.7 MAP(inHg) 18.9 RPM(/min) 1646 VSS(mph) 48 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 3.996 TP(%) 12.9 O2S B1S123-B2S1--- O2B1S1(V) 0.740 SHRTFTB1S1(%) -5.5 O2B1S2(V) 0.700 O2B1S3(V) 0.750 O2B2S1(V) 0.780 SHRTFTB2S1(%) -1.6 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 9.0 ETC(°F) 165 SHRTFT1(%) -0.8 LONGFT1(%) 5.5 SHRTFT2(%) 3.9 LONGFT2(%) 4.7 MAP(inHg) 11.2 RPM(/min) 1479 VSS(mph) 48 SPARKADV(°) 36 IAT(°F) 37 MAF(lb/min) 1.575 TP(%) 0.4 O2S B1S123-B2S1--- O2B1S1(V) 0.775 SHRTFTB1S1(%) 3.9 O2B1S2(V) 0.795 O2B1S3(V) 0.735 O2B2S1(V) 0.290 SHRTFTB2S1(%) 4.7 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 4.7 ETC(°F) 165 SHRTFT1(%) -3.1 LONGFT1(%) 5.5 SHRTFT2(%) -1.6 LONGFT2(%) 6.3 MAP(inHg) 8.9 RPM(/min) 1340 VSS(mph) 44 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 1.253 TP(%) 1.6 O2S B1S123-B2S1--- O2B1S1(V) 0.850 SHRTFTB1S1(%) -3.9 O2B1S2(V) 0.050 O2B1S3(V) 0.770 O2B2S1(V) 0.095 SHRTFTB2S1(%) -1.6 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 14.9 ETC(°F) 165 SHRTFT1(%) -2.3 LONGFT1(%) 12.5 SHRTFT2(%) -0.8 LONGFT2(%) 11.7 MAP(inHg) 18.9 RPM(/min) 1653 VSS(mph) 45 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 2.111 TP(%) 0.4 O2S B1S123-B2S1--- O2B1S1(V) 0.215 SHRTFTB1S1(%) -1.6 O2B1S2(V) 0.835 O2B1S3(V) 0.720 O2B2S1(V) 0.780 SHRTFTB2S1(%) 0.8 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 5.1 ETC(°F) 165 SHRTFT1(%) -3.1 LONGFT1(%) 5.5 SHRTFT2(%) -4.7 LONGFT2(%) 6.3 MAP(inHg) 9.2 RPM(/min) 1313 VSS(mph) 43 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 1.266 TP(%) 0.0 O2S B1S123-B2S1--- O2B1S1(V) 0.060 SHRTFTB1S1(%) -3.1 O2B1S2(V) 0.060 O2B1S3(V) 0.710 O2B2S1(V) 0.790 SHRTFTB2S1(%) -2.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 3.9 ETC(°F) 165 SHRTFT1(%) 0.0 LONGFT1(%) 0.8 SHRTFT2(%) 0.0 LONGFT2(%) 0.0 MAP(inHg) 8.9 RPM(/min) 1039 VSS(mph) 34 SPARKADV(°) 33 IAT(°F) 37 MAF(lb/min) 0.999 TP(%) 0.0 O2S B1S123-B2S1--- O2B1S1(V) 0.805 SHRTFTB1S1(%) -1.6 O2B1S2(V) 0.770 O2B1S3(V) 0.710 O2B2S1(V) 0.065 SHRTFTB2S1(%) 0.0 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 3.1 ETC(°F) 165 SHRTFT1(%) -1.6 LONGFT1(%) 0.8 SHRTFT2(%) 0.0 LONGFT2(%) 0.0 MAP(inHg) 9.7 RPM(/min) 852 VSS(mph) 19 SPARKADV(°) 32 IAT(°F) 37 MAF(lb/min) 0.843 TP(%) 0.0 O2S B1S123-B2S1--- O2B1S1(V) 0.065 SHRTFTB1S1(%) 0.8 O2B1S2(V) 0.320 O2B1S3(V) 0.705 O2B2S1(V) 0.080 SHRTFTB2S1(%) 2.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 21.6 ETC(°F) 165 SHRTFT1(%) -3.1 LONGFT1(%) 7.0 SHRTFT2(%) 0.8 LONGFT2(%) 6.3 MAP(inHg) 26.0 RPM(/min) 2111 VSS(mph) 24 SPARKADV(°) 23 IAT(°F) 37 MAF(lb/min) 9.326 TP(%) 62.0 O2S B1S123-B2S1--- O2B1S1(V) 0.245 SHRTFTB1S1(%) 3.1 O2B1S2(V) 0.870 O2B1S3(V) 0.630 O2B2S1(V) 0.100 SHRTFTB2S1(%) 0.0 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 OL FUELSYS2 OL LOAD_PCT(%) 51.4 ETC(°F) 165 SHRTFT1(%) 0.0 LONGFT1(%) 7.0 SHRTFT2(%) 0.0 LONGFT2(%) 6.3 MAP(inHg) 28.6 RPM(/min) 3343 VSS(mph) 47 SPARKADV(°) 23 IAT(°F) 37 MAF(lb/min) 16.098 TP(%) 100.0 O2S B1S123-B2S1--- O2B1S1(V) 0.875 SHRTFTB1S1(%) 0.0 O2B1S2(V) 0.885 O2B1S3(V) 0.860 O2B2S1(V) 0.900 SHRTFTB2S1(%) 0.0 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 10.6 ETC(°F) 162 SHRTFT1(%) -3.1 LONGFT1(%) -1.6 SHRTFT2(%) 0.0 LONGFT2(%) 5.5 MAP(inHg) 10.3 RPM(/min) 1700 VSS(mph) 57 SPARKADV(°) 36 IAT(°F) 37 MAF(lb/min) 1.730 TP(%) 0.0 O2S B1S123-B2S1--- O2B1S1(V) 0.850 SHRTFTB1S1(%) -1.6 O2B1S2(V) 0.085 O2B1S3(V) 0.785 O2B2S1(V) 0.690 SHRTFTB2S1(%) -7.8 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 6.3 ETC(°F) SHRTFT1(%) LONGFT1(%) '> SHRTFT2(%) LONGFT2(%) MAP(inHg) RPM(/min) VSS(mph) SPARKADV(°) IAT(°F) MAF(lb/min) TP(%) O2S O2B1S1(V) SHRTFTB1S1(%) O2B1S2(V) O2B1S3(V) O2B2S1(V) SHRTFTB2S1(%) OBD ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 11.0 ETC(°F) 162 SHRTFT1(%) -3.9 LONGFT1(%) 4.7 SHRTFT2(%) -1.6 LONGFT2(%) 3.9 MAP(inHg) 13.6 RPM(/min) 1626 VSS(mph) 52 SPARKADV(°) 36 IAT(°F) 37 MAF(lb/min) 1.877 TP(%) 2.0 O2S B1S123-B2S1--- O2B1S1(V) 0.440 SHRTFTB1S1(%) 1.6 O2B1S2(V) 0.830 O2B1S3(V) 0.705 O2B2S1(V) 0.840 SHRTFTB2S1(%) 2.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 16.9 ETC(°F) 162 SHRTFT1(%) -2.3 LONGFT1(%) 12.5 SHRTFT2(%) -0.8 LONGFT2(%) 11.7 MAP(inHg) 20.1 RPM(/min) 1766 VSS(mph) 53 SPARKADV(°) 34 IAT(°F) 37 MAF(lb/min) 4.708 TP(%) 20.8 O2S B1S123-B2S1--- O2B1S1(V) 0.260 SHRTFTB1S1(%) -3.1 O2B1S2(V) 0.640 O2B1S3(V) 0.690 O2B2S1(V) 0.115 SHRTFTB2S1(%) -2.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 12.9 ETC(°F) 165 SHRTFT1(%) -4.7 LONGFT1(%) 12.5 SHRTFT2(%) -2.3 LONGFT2(%) 11.7 MAP(inHg) 15.9 RPM(/min) 1676 VSS(mph) 53 SPARKADV(°) 36 IAT(°F) 37 MAF(lb/min) 2.550 TP(%) 4.3 O2S B1S123-B2S1--- O2B1S1(V) 0.060 SHRTFTB1S1(%) -3.1 O2B1S2(V) 0.080 O2B1S3(V) 0.695 O2B2S1(V) 0.795 SHRTFTB2S1(%) 0.8 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 7.8 ETC(°F) 165 SHRTFT1(%) 1.6 LONGFT1(%) 4.7 SHRTFT2(%) 0.8 LONGFT2(%) 3.9 MAP(inHg) 11.8 RPM(/min) 1581 VSS(mph) 52 SPARKADV(°) 36 IAT(°F) 37 MAF(lb/min) 2.139 TP(%) 4.3 O2S B1S123-B2S1--- O2B1S1(V) 0.685 SHRTFTB1S1(%) 0.8 O2B1S2(V) 0.060 O2B1S3(V) 0.680 O2B2S1(V) 0.800 SHRTFTB2S1(%) 6.3 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 9.8 ETC(°F) 165 SHRTFT1(%) 2.3 LONGFT1(%) 12.5 SHRTFT2(%) 3.1 LONGFT2(%) 11.7 MAP(inHg) 21.9 RPM(/min) 1878 VSS(mph) 51 SPARKADV(°) 30 IAT(°F) 37 MAF(lb/min) 5.451 TP(%) 27.5 O2S B1S123-B2S1--- O2B1S1(V) 0.160 SHRTFTB1S1(%) 2.3 O2B1S2(V) 0.080 O2B1S3(V) 0.680 O2B2S1(V) 0.395 SHRTFTB2S1(%) 7.0 OBD OBD2 ------------------ DTC_CNT 1 FUELSYS1 CL FUELSYS2 CL LOAD_PCT(%) 5.9 ETC(°F) 165 SHRTFT1(%) 2.3 LONGFT1(%) 4.7 SHRTFT2(%) 1.6 LONGFT2(%) 6.3 MAP(inHg) 9.5 RPM(/min) 1544 VSS(mph) 51 SPARKADV(°) 35 IAT(°F) 37 MAF(lb/min) 1.598 TP(%) 0.0 O2S B1S123-B2S1--- O2B1S1(V) 0.790 SHRTFTB1S1(%) -0.8 O2B1S2(V) 0.175 O2B1S3(V) 0.750 O2B2S1(V) 0.765 SHRTFTB2S1(%) -1.6 OBD OBD2 ------------------