obd II code PO 300 random multiple misfire changed cap, rotor, plugs & wires

What is your question?

1997 Chev S-10 4.3L...Ran great after changing everything and mpg was back to normal now hesitates and sputters as it did before I changed everything...code keeps saying multiple random misfire and am now getting 12 mpg where before was getting 24mpg after tune-up

What makes this problem better or worse?

doesn't matter if engine is cold or hot

How long has your 1997 Chevrolet S10 had this problem?

about 500 miles after changing everything