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Hi , seems to me a lot of parts have already been replaced on the engine management , but I work considerably on gm products . The engine control module has retained memory have you cleared all codes before operating engine if so and problem still exist disconnect battery and fasten the negative and positive cables together to discharge ECM internal backup battery approximately 30 min. after that process properly connect battery cables back onto battery and start engine check for operation if still running rough, with tech2 check the MAF (mass air flow) sensor located just after the air filter box ,also make sure the air filter doesn’t have any obstruction and air filter box is properly fitted onto air filter.The MAF sensor is very important to engine operation because it measure air coming into intake and the ECM determines how much fuel to inject if MAF sensor malfunctions ECM gets incorrect air mixture readings .I hope this helps , hard to diagnose without the vehicle literally in front of you.
When the problem first started there wasn’t any codes and no work was recently done. It got worse and the cam sensor code came up changing it didn’t work.
How about the basics rotor cap wires plugs?
If this is the 4.3 they have a plastic base that breaks on the distributor that causes the cap to wobble and misfire.I have seen guys zip tie their cap in place top to bottom as a elcheapo repair.
These era 4.3 and 5.7 gm engines were pretty particular on what tune up parts they liked.
I have had napa caps and car quest caps that misfired out of the box on the 4.3 and 5.7 gm/delco caps have been my best bet,I run a fleet of about 25 of these year trucks.
Good luck.
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