Okay, here's another interesting noise for y'all to diagnose...

When the rpms hit about 3k or so, i start to hear an air sucking noise... Now because this only happens while driving, I cannot tell if it is from the engine compartment (which i think it is) or from under the body... all I know is that it isn't my intake, because it makes the same noise with the stock intake. Also, I've recently changed the vacuum lines, but the noise didn't happen until a few days afterward... any suggestions as to why this might be happening? Oh yeah, and it's a 95 blazer lt w/ the 4.3 cpi vin w engine.

Ciao

Oh yeah, and I also equate that noise with a lack of power... it almost seems as though i was trying to go up a hill in 4th... help?

could be a pluged cat. mines pluged and once it hits about 2,500 it sounds like a turbo. also its got a lack of power and it has serious problems going up a hill. the trucks sitting until the new cat comes in. i got a catco off ebay for $40 and $10 for shipping. i'm driving the mustang until the trucks fixed. it sucks with the gas it uses.

maybe an exhaust leak too when its cold out look under and see if its leaking if not possibly a plugged cat