What HW version is your router?
What FW version is currently loaded?
What ISP Service do you have? Cable or DSL?
What ISP Modem do you have? Stand Alone or built in router?
What ISP Modem make and model do you have?
What kind of gaming are you referring too? PC or Game Console?
Try single mode G or mixed G and N?
What security mode are you using? WEP, WPA or WPA2? Preferred is WPA2 and Cipher type to AES only if your device support this.
Any other Wifi in the near by area?
Any cordless phones?
Yes this is a gaming router, doesn't mean it's perfect for gaming over WiFi though. It's just standard WiFi.
I prefer gaming over wired has it's less headache on any router. Wired is preferred, both for PC and console gaming. 2ms ping differences isn't something to get bothered by. I do agree that 100ms ping happening more often is cause for troubleshooting and seeing what can be done to find the cause.
Have you reviewed the gaming and gamefuel stickies for any help using Gamefuel settings?