Hesitation and Hissing Sound

Hello, I have a 95 Blazer with 122,000 miles. A few days ago, I noticed my Blazer had low power on highways and going up hills. It would drive fine after sitting for a long period of time but after driving a few
miles it had diffulty accelerating. Two days ago I had the fuel filter changed and it helped a little but it still wasn't accelerating properly. It idles fine.
This morning, on my way to work, the problem got worse. From a stop, I had to push the gas to almost full throttle to get it going and it would hesitate pretty badly until I got the truck moving again. This was the situation for about 8 miles. I get about three miles from my job, and the truck started accelerating pretty good again but now I get a hissing/windy sound when I accelerate. My guess would be a leaky hose or vacuum somewhere but I'm not sure. At this point I noticed my braking was a little more difficult. Does anyone know what the problem could be? Are there any simple solutions I could try before taking it to a mechanic.
Here are some things I had replaced since I owned the vehicle. 3.5 yrs/~45K Fuel filter, 2 days ago. EGR Valve, twice last time 6 mo/~9K ago Plugs and wires, ~30K ago Fuel Injector, ~30K ago Exhaust system (not including the CAT), 10/mos/~15K ago
Thanks, Rich
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Possible exhaust restriction. Put a vacuum gauge on it and see if the vacuum decreases as you slowly increase engine speed. Sometimes a pipe will collapse inside a connection or the muffler.
The fact that the braking is poor might suggest that you have a major vacuum leak, but usually the engine will not idle if that is the case. Lynn
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We have had 2 cars do this. In both cases the catalytic convertor innards had broken up and plugges the muffler. The hiss was in the exhaust. Listen to your exhaust when idling. You should hear a bit of bum bum bum bum, if it hisses you muffler is likely plugged. Dan
On 18 Feb 2004 08:14:42 -0800, snipped-for-privacy@yahoo.com (Rich) wrote:

Colorado Springs, CO My advice may be worth what you paid for it.
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