Recently my 2002 Chevy Blazer 4wdr 4.3L went into LIMP mode. I was driving, turned onto the highway and it just lost its power. The vehicle still runs but only goes up to 35mph give or take basically 2nd gear(2100rpm).

I went to the auto parts store and ran codes. I received the following:
P0101, P0155, P0171

So fast forward to today. I take it to a shop for an estimate. They claim at this point that my cat converter is bad. They claim to need to replace it and the 02 sensors surrounding it.

For this repair they are asking $650+

I looked online for estimates and that seemed downright outrageous. I just need advice on what to do from here.

I work on computers not cars, any advice is greatly appreciated. Thanks!

 

On a side note upon receiving my car back from the shop.(My parents picked it up) I noticed taking it for a test driving that now the intake is trying to suck air loudly. When i drove the car yesterday to the garage it had no such noise, drove fine, didn't sound that awful just didn't have the power.

Thanks again!

 

I'd start by changing the air filter and cleaning the MAF sensor, and if that doesn't fix it, replacing it. Get cleaner specifically for a MAF sensor.
More information on the MAF code (P0101) is found here.

I'm sure someone more knowledgeable than I will come in and give more complete advice.