Vacuum leak - top end power loss
 

I've got a '96 Chevy blazer 4x4 2dr with 205K on it. I've owned this beast for about 6 years now and must say it's been a great vehicle.

When I got this vehicle it had ~150K on it & the intake leaked from the day I got it. Oddly enough she'd open up when the seasons changed (temperatures). This summer however at 199K The fluid opened up for the last time and I couldn't keep anything in it for longer than a 30 mile trip.

Time to change the LIM - While I was in there I replaced plugs, wires, rotor cap & the Serp belt. Soon after it was back together the radiator cracked - Replaced it too.

Truck ran great for 4000miles. My MPGs increased from 15 or 16 to nearly 20mpgs. No complains.

2 Weeks ago the truck was starting hard (Although would reliably start on the first try). I'd crank it for anywhere from 3-5 seconds and then she's turn over. Oddly enough it's start right up cold. When it was warm is when it'd start rough.

THe CEL came on & gave me an 02 sensor code, upstream bank 2 - The day before I replaced it I started losing significant power and could hear a whistling noise.

I replaced the 02 sensor and the CEL was back on. This time a P0101 - MAF sensor. I checked all the vacuum hoses which I could see. I can hear the sucking/whistling noise clearly but I can not pin point it. I want to say it sounds like it's coming from the exhaust, but it's a loud noise heard only when you get on the gas hard at idle or accelleration.

I have nearly no top end power - If I baby it off the line I can go faster than putting the pedal to the metal. Dogging it gets me up a hill quicker. Running it to redline the engines screaming as I decellerate up the slightest grade-no power at the top end.

I also had a rattling noise in what I thought was my CAT for a while (for a good 10K miles)...recently it got worse...but I didn't notice any power issues...then the sucking sounds started, the 02 sensor code/replacement. If it means anything too I never checked my tranny fluid before as it didn't use anything and shifted very nicely (of course I kept my eye on it when I bought the vehicle, but it proved very reliable so I stoped the frequent checks)...Going up a hill 2 weeks ago something didn't seem right in the tranny, engine screaming, shifting hard, this is around/ just after the problem started. I pulled off checked the trans fluid and found it a little more than a quart low. Not sure if this has anything to do with it but I used to drive a GMC 3500 with a 350 vortec in it for work and I had a vacuum leak that would randomly suck up fluid and dump it in the engine - Would blow a house sized smoke ball out of the exhaust at a red light. Truck seemed to run find though other than that - Yes it was pretty gnarly.

I'm clueless folks - I dont see any vac lines off...Any advice would be well taken. I know this was long winded but it there have been a lot of repairs lately to this old girl. I didn't want to miss anything that might be evidence.

Thanks
Dustin