I would recommend performing a compression test. That is the most basic and important thing to do when trying to tune/diagnose an engine.
It is a step I would not skip. Do it now.
Then, when finished, put a socket on the front crankshaft bolt. Also Loosen the distributor cap, pulling it aside exposing the rotor so you can watch it as it moves. Very important.
Next,.. Turn the engine slowly by hand, watching the timing mark on the balancer. Pull it to 0 degrees top dead center. At this point, watch the distributor rotor, turn the engine SLOWLY backwards, watching thr rotor. As soon as the rotor starts to move, look at the balncer to see how many degrees the engine turned BEFORE the rotor actually moved. If you turned it more than 12 degrees, the timing chain and gears are worn and may need replace. 12 degrees is a rough "rule of thumb" .
12 degrees or more of slack in the chain is pretty indicative of a worn chain set needing replaced.
After these 2 tests you will know which direction to go next on how to get er runnng good. I gaurantee it.
Fact is stranger than Fiction