76 camaro car

This is my last effort before I scrap this car. Car is a 2001 accord with a 2.3 engine. The engine ran fine months ago. The car sat for maybe 3 or 4 months. Now when I start the car it runs but has a miss. Throwing misfire codes on all cylinders. I thought it might be bad gas so I pulled the fuel pump and siphoned all the gas out of the tank. I bought 5 gallons of 93 octane gas and put it in the tank. I started the car and still have misfire codes and hear what sounds like pretty bad rods rattling. I have replaced the plugs, plug wires, distributor cap and still have the misfire and knocking sound. Is it time to abandon this project? Engine has 171k on it. Thanks

SpeedRacerEX-R

How are you reading the codes? When is the last time you changed the fuel filter?

MAD_MIKE

Verify the intake and exhaust valves are properly adjusted. Too tight adjustment will cause a misfire when the engine heats up.
What do the plugs look like? Are they the correct plugs for the application?
How old are the plugs/wires/cap/rotor?
Have you verified the inside of the cap is dry and clean? Spray WD40 inside cap and wipe it down with a clean rag, verify the terminials and rotor tip are not corroded.
Verify spark is blueish white. Orangish spark indicates fault in the ignition system, either poor secondary side or low primary side voltage.
Verify all the bonding grounds/jumpers are clean and tight.
Verify the battery terminals are clean and tight.
Verify the battery is holding a full charge.
Verify base timing is correct. Warm up engine til fans come on, turn off. Jumper blue two wire connector, connect timing gun to #1 cylinder nearest timing belt, verify the base timing is on the red painted 3 notched timing marks.
Verify the damper outer ring has not slipped causing erroneous timing marks.
If timing is off check the timing belt is properly installed/adjusted.
Verify fuel pressure.
Dump Seafoam into the oil, same with gas tank and intake manifold to remove any possible varnish build up on the valves/valve stems causing sticking or carbon buildup on the combustion chamber causing detonation.
Verify compression test.
Verify no loss of coolant.
Verify the EGR passage in the upper plenum is not coked/gummed up.
Verify the EGR valve is properly functioning.
Verify no air leaks.
Verify the pickup sensors on the oil pump housing are not dirty/coated in grime.
Verify the oil does not smell like gas, change it if suspect.
Verify oil pressure.

76 camaro car

Would any of these cause rods to rattle once the engine gets warm?