Sluggish '92 S10 Blazer (CPI 4.3 Vortec engine) after multiple repairs

Several months ago, my car (Bubby), started running rough. I changed his spark plugs, wires, and distributor cap. Bubby started running worse. He would hesitate on inclines (only getting to about 20 miles per hour) and would accelerate poorly, until one day, while leaving my house, I couldn’t get him to go more than 7-10 miles an hour without stalling. I had him towed to a family friend who is a professional mechanic. He started Bubby right up and took him for a drive without issue… except for coolant leaking into the floor board of my car. There was now a leak in the heater core. The simple and cheap solution was to bypass the heater core (which he did).

The car was running now, but still running poorly. I took my car to a mechanic my cousin goes to because she says they do great work. They replaced the fuel pump and fuel sending unit. The car was still running poorly and still felt unsafe to drive. They recommended I take Bubby to another mechanic nearby who has experience with older blazers. After some issues (they did the repairs without permission, ugh, and cost me a lot of money) they replaced the fuel injector and distributor. When I finally picked up the car, he ran great… for two days. He is now running slightly rough at idle, two days later he now is very sluggish. Yesterday, I had the gas pedal nearly all the way down and he was accelerating quite slowly, the check engine soon light came on briefly (about 3-5 seconds, and that has never happened since I have owned the car).

The sensation I get when driving Bubby is sort of like driving through Jello, or driving with the emergency brake on (it’s not, I checked). I was told by one of the mechanics that I need to replace the Catalytic Converter, but I don’t have any idea if that could cause this kind of issue. I don’t have any idea what else to do. If anyone has any ideas, I’m certainly open to hearing them.