catalytic converter

Background: 97 Passat with over 250K miles on it. .210 nozzles and rebuilt pump installed in July. After the installs of fuel system parts the milage was great, as high as 58.2 MPG with an avg of 48 and 38 while pulling a 1100 lb. teardrop trailer.
Problem: During the last tank of fuel there has been a odd smell and power seem to be down and milage is down.
Question: Is it a pulled catalytic converter?

could just be a bad batch of diesel, plugged intake or a bad cat

try a new tank of fuel first then pull off the egr and look at the intake, lastly check the cat

I forgot to mention that I cleaned the intake and intercooler less than 6 months ago, so I fell pretty sure that's not the issue.

Unless you are required to have your vehicle emissions tested, most are removing the cat for good. Keep it though in case the laws change in your area as they are not cheap to replace. A skilled person with a skil saw can cut clean and straight just in front of the converter but behind the flange, and again after the converter. Get some stainless or aluminized tubing and weld it into place. But, bad fuel could do it too.