Knock / Misfire?

[sr20drft]

Ok was on my way to my buddies place yesterday, and i was merging onto the highway and when my car hit around 5500rpm @ WOT it made an odd blipping sound from the exhaust and just didn't accelerate. It did it again at the same rpm when I tried it again.

Then it started leaking somewhere under my heatshield, sounded nasty.

Would this be knocking or misfiring?

Causes?

[ryan hagen]

my ka24de with a turbo is doing the same thing, 5000-5500 rpm any gear it alomst feels like its missing.