1987 pontiac firebird v6 2.8l

my 1987 pontiac firebird v6 2.8l is still stalling on me. stalls about 4 times in a row and sometimes the “check engine” light comes on and stays on. It also still has that knocking noise to it. my car only has 120,000 miles. when I accelerate my car jerks, bogs, and knocks. I heard it could be my timing belt? What else could be causing my car to stall and run rough?

so far i just replaced the spark plugs, spark plug wires, distributor cap, rotor, fuel filter, and the idle air control valve. so far this has cost me about $300 I was told by auto zone and car x to replace these parts, but the problem still continues…