Got a 94 LX 1.8 DOHC. Every now & then, I get a bad rattle under the car (sounds like in the exhaust) and a BAD air noise like a blowoff valve from a compressor. Yhe car will then act like it's running on 3. Any idea's? I think the exhaust is plugging, causing too much back pressure, but I'm a suspension & stereo guy. Engine guru's, Hear me!!!

 

check your cat it could be clogged and has caused an exhaust leak just and idea it could be and couldnt be the problem

 

I'm hoping that's it. Thanx for the head's up.