It seems my second cylinder isn't firing. I have a lot of exhaust noise when accelerating. But here's the weird part the other day I went for a 45 min drive and just like that the secon d cylinder started firing and wow what a difference it made. Ran great all day long after that but when I got home and let it sit overnight my problem came right back. Any idea's?

 

valve adjustment, plug wire shorting / grounding out
does it smoke at all?
how does the spark plug look?

 

First thing to check would be plug and plug wires as abecedarian said. I'm assuming you've already checked them?

Rob

 

Tune up time?
check the routing of the wires. The wire for the #2 plug may have touched the manifold or another hot surface...

 

Spark plugs and plug wires have already been replaced and it doesn't smoke at all.

 

well, I was curious how the plugs look. basically, looking for evidence of combustion, or lack thereof: deposits, etc.
have you checked that #2 injector is getting a pulse with a "noid" light?
have you done a compression check?