Just recently brought a 95 Prelude Si with a JDM H22 Swap. When I first got the car about a month ago it ran fine. Came with a VAFC. I started having this rev issue within a couple weeks ago. At WOT when I try to get in on it the car feels like it falls flat on its face around 6800-7000 rpms and struggles really hard to rev past that. It also makes a weird noise that sounds like a bunch of air rushing out of the exhaust but its really loud, followed but a wind tunnel sound all coming from the rear of the car. Hard to describe but its a really weird noise. It does have hesitation sometimes, cuts in and out when it wants to. I suspected the VAFC was the issue so I disconnected it and routed all wires back to their original spots on the ECU making sure all connections were secure. That didn't help the issue. VTEC still engages, no CEL. When I get on it at about half throttle it pulls fine all the way up to redline, only has this problem at WOT. Free revs just fine. What could this be? Any ideas?

(I'll try to get a video posted of the noise its making, I've never heard anything like it from a car)

 

catalytic converter maybe

 

Thanks for the reply. I suspected that was an issue also...I'm going to get a high flow cat put on sometime in the near future. I can't stand being deprived of my power lol

 

a high flow cat will help ? with the depriving of the power issue

 

First thing I would look at is the TPS. It could be a bad spot somewhere in the band. Next would be the MAP sensor as I had the same exact problem and using a vacuum pump I found the MAP sensor was bad but wasn't throwing a code as 'though it was out of specs it wasn't bad enough to throw a code.

 

yeah I will go with the map sensor check the wiring as well