1995 blazer Engine Performance problem

1995 Chevy Blazer 6 cyl Four Wheel Drive Automatic 222000 miles

A week before this happened I was driving through the rocky mountains in colorado. This engine runs great for its's age. Last sunday night I started the blazer to put it back into the driveway ran fine. Next morning I started it up and the engine ran ruff. I put a scanner on it this weekend and I am getting a code P0302 the misfire for number 2 cylinder. Also the Engine Service Soon Light is blinking with strong smelling exhaust. I disconnected the plug wire checked for spark and I have a spark. Is there a common issue with these 4.3 litre engines that may cause The P0302 code. This engine has been very durable and burns very little oil.

One of the most commom problems is owners do not do needed tune up or service.
What is the mileage on last tune up?
What is repair and service history?
How is plugs and fuel filter and cap and wires?
Good AC plugs?

The engine was cutting out a year ago so I replace the cap/rotor which were gm, also wires napa and AC plugs. I may try the cap and rotor again. I switched wire 2 and 4 both on the plugs and cap but still got a misfire on cylinder 2. Actually this blazer has had proper maintenance since the wife worked for an automotive center that maintained and repaired when needed

Pull plugs and see if wet or dry or black on end.
Got good compression and fuel pressure and good hot blue spark to all plugs?
What is engine code?
Old style or new style flat top dist?
Any other codes?