97 Sunfire SE 2.2L 3 sp

Has recently had both coil packs, plugs, wires, new exhaust system from behind manifold, air filter and fuel filter installed.
I am having a P0300 that comes and goes as it likes but I have a constant idle/acceleration misfire.
Runs smooth on the freeway but getting up to speed is hell.
Sounds like it has an exhaust leak, a loud ticking like sound from the back top/middle of the motor.

If i watch the misfires on the Genysis scanner, they start at number 4, then number 3, then 2 and eventually 1 will start misfiring.
I have been chasing this problem for months with no luck now.

Any input/advice/ideas would be much appreciated

thanks in advance