My stock 08 is having a bogging issue. Most times it starts fine, idles a bit low (1200ish) and is numb off the line and slow to respond to throttle input. with occosional stalls and backfires. At times I can only get 5000 rpm and 35 mph then I get the power back and can reach top speed/rpm. I've got a spare plug wire to try switching around with the ones on it. Any ideas or suggestions of what to check (and how) would be great. Thanks