dtc p0441 and p0308

here is the deal, i recently had installed headers on my 97 camaro ss,6-spd,5.7 ltr lt-1, 148k. i have replaced all the vaccum hoses, switches and gas cap,the plugs are ngk tr55 with msd 8.5 mm wires about 1 month ago.well i keep getting p0441 after 50 or so mi of driving and today the ses light was flashing and i pulled p0308.i really dont know whats going on and need to get it inspected out here in tx soon. if anyone has any ideas please let me know and i have taken it to a shop and wasted $70 dollars on a diagnosis which i replaced the part with no resolve.so any help will be greatly appriciated.

r.swiger

Wasted 70 dollars! If you don't know the answer to your problem then what is a fair price to pay to somebody that does! Is the ignition components up to snuff on cylinder #8? burnt wire on your new shiny headers maybe?