check engine blinking at high rpm.

[rippinitup]

i changed out my intake manifold gaskets a few months ago, everything been running fine since. about a month ago i installed a corsa sport exhaust and an airaid intake tube. the other night i was driving and i had the truck pull to about 5k rpms and the check engine light started to blink for about 10 seconds. so i figured to give it a go again and once it got near 5k rpms the check engine started blinking again.

the truck idles fine drives fine. dont notice any loss in power.
i changed all the spark plugs back in april. any idea whats going on? i know it means misfire. how can i find out which cylinder is misfiring?

 

[Chiggy]

Throw a scanner on it and see if it's a random or it tells you what cylinder.