NAJDMDC4

i have a jdm h22a in my prelude and i was driving today and my car is usually loud but it was unbelievably quiet... like i would drive and at about 3k rpm in 2nd gear itd make a pst sound and get quiet and stay quiet throughout all the gears... and when i got on it it wuldnt engage into vtec itd just get up to 5k rpm and blog. cant think of the word but it wont go past 5k rpm or get into vtec.
can anyone tell me what the problem could be

dirty c

clogged cat?

Muncher

Id say check your exhaust and intake boh for clogs, then go from there.

NAJDMDC4

i drove it yesterday and the car choked at 60mph and blew out black smoke from the exhaust for like a split second and i drove it today and the car seems fine but still unusually quiet.
i did an oil change over the weekend and added bg oil treatment it said reduce engine noise but i dont think that could be it
i checked the intake and exhaust for clogs and checks out clean is there anything else

MuffinMan7580

Sounds like a bunch of honda fail to me lol. Seriously though, sounds like a clogged cat. Right after you drive it, look underneath the car and see if the cat is glowing red.

Fabrik8

Almost sounds like it's running really rich, might have a sensor failure or a vacuum leak. It could be a lot of things if it's a swapped engine. Strange that you're getting a 5kRPM rev limit without a CEL though. Between that and the VTEC problem, it sounds like it's in limp home mode.

NAJDMDC4

the car is running a little rich but i had a vacuum leak for a lil while but never affected the sound or vtec...
the cat does not glow red at all