THIRD CATALYTIC CONVERTER SINCE SEPT 2011. Bought our 2004 xB in 2011 with 112k miles. It has just surpassed 200k and am getting 3rd cat installed since that time. Last weekend had torrential rain /puddles etc. Drove fine until following Monday. About 5 min into running errands, car stalled and would not restart. What is up with my cat problems?

 

Sounds like you have two problems. As for the no start after torrential rains, I'd check for water down the spark plug bores under the coil packs. The other thing could be water getting to your mass airflow sensor - especially if you have a cold air intake. (Ask me how I know that.) Any codes?

When it comes to cats, you have something wrong there. I have two 2006 xBs with 100,000 and 175,000 miles on them - with original cats. One thing that will kill a cat is too much fuel getting to it. How is (was) the car running? Any codes?

 

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Thanks for the reply 2Stroked...it Was running fine. I replaced the plugs and coil packs last summer. Coil packs/plugs are dry. It has a K&N cold air intake. I have not cleaned/changed filter ever. So air intake could be an issue. Mechanic said prior cat was a "universal" type and shouldn't have been on car. Now a manifold gasket needs to be replaced. He did mention something about the MAS. Has that loud exhaust pipe sound while driving. Haven't read codes. I work nights--will get to it soon and get back to you. VSC, TRAC-OFF and engine light are on. I will say it felt like I had quicker acceleration after the new cat was installed.

 

*Actually It's an AEM cold intake system.

 

The "loud exhaust pipe sound" is probably caused by the manifold gasket issue your mechanic noted. A cheap "universal" cat will do exactly what that one did - crap out early. I would definitely service the K&N filter exactly as the instructions on the recharge kit say. And do not over-oil it! Let's see what the codes say.

 

Here are the codes from Autozone:
C1201-engine control system malfunction
C1336- zero point calibration of
P0171-Bank 1 system too lean

Thanks in advance...