If my cat is clogged what will the symptoms be? My gas milage has seemed to be about 17mpg, down from about 23 or so. And there is a whooshing sound when I get into the boost. Can anyone help me??

Chris in Buffalo

Since you have a turbo I'd check the hose for holes. The one hos that is notorious for holes it the Air mass meter to turbo. Be sure to check the bottoms of the hoses around the clamps. One hose that would produce the wooshing sound if lose or has a hole in it is on the intercooler to throttle body side. One time I did not clamp the hose down tight enough at the t-b and it cams lose causing poor as crap MPG and a wooshing sound. Also on my 92 745TI a hole in that hose caused similar symtoms.

If your hoses are ok you can check the cat by removing the check plug just forward of the cat. Be sure to coat it with pb blaster as I am sure it'll be stubborn. I have never been able to work that plug free on my 90 765TI!

just out of curiosity..when did you change your oxygen sensor last?

Chris - I'm having the same issues you are (94 945T) - and I just changed my 02 sensor (101k). It didn't make a bit of difference in performance/mileage. I'd love to know what has reduced my performance/mileage too. If you figure it out, please let us know! Thanks. I'll do the same.