Back from a long trip my car started getting really loud and bogged down. The loud noise seems to be coming from under the cabin. I am also getting error code P0442, which is a EVAP leak. Any idea what could be the culprit??

Have you examined your exhaust system?

P0422 is not EVAP - not sure where you are receiving your information.
Search: http://www.obd-codes.com/p0422

Seems pretty obvious why it got louder...

Im new to cars and not really sure where to start with all of this. I recently had my flex pipe completely replaced, could it be somehow the cause? If not, how would you suggest I start to find the problem? Thanks!

Look under the car, check out the exhaust system. Seems as if not only your Flex Pipe replacement went sour, it threw a code too, most likely for the rear 02 sensor.

Just look at your exhaust for starters, I bet the downpipe came disconnected from the Manifold or something of the such. Just make sure all piping is connected & sealed.

Originally posted by 2ndGen-ElTalon
it threw a code too, most likely for the rear 02 sensor.

No. I already gave the link/info for the code, and it is not for the rear oxygen sensor.

Code4 i appreciate your help but YOU misread my original post. I said I had code P0442 and you misread it and posted for code P0422.

Right, I did miss that part, however I was going off of your thread title, which you typed incorrectly.

In any case, the rear oxygen sensor is not related to either code that you typed, P0442 or p0422.

YES, literally just caught that 2 seconds ago...

Curious on the evap code. Could be something as simple as gas cap not all the way on, or you need another one. But what you are describing is catalytic converter problem. Progressively getting slower (usually starts happening over a long ride), with a louder exhaust noise emanating from under the car. What's basically happening is the equivalent of blocking off the exhaust; the gases can't get out easily.

As stated, check out your exhaust. To check the cat simply disconnect it at the front of the cat and take her for a quick, noisy spin. If she no longers bogs down, then its probably a clogged cat. If you get under there and see a bad connection/gasket, fix that first before testing the cat.