I recently purchased a 964 with the following known mods: No cat, B&B muffler, bored throttle body, ported heads web cams and some internal "turbo" components. My question is this:
The O2 sensor at the cat bypasss pipe is disconnected.... when connected the car will not idle or stay running. Is this the sign of a bad sensor or a necesity of the mods??? It also appears that the MAF sensor has been opened and "calibrated". Car runs well.... but I have nothing to compare it to.
Thanks in advance for any help.

Rob

 

I have my O2 sensor disconnected on my '87 930's GHL's and have not noticed any differences, other than it take a little longer to warm up. I also think it helps enrichen the A/F a little. This doesn't really answer your question, but hopefully it helps some.

If your in Kansas City, you need to take it to Stephan at Imagine Auto for any work/advice. Between him and Steve at Rennsport, you won't two nicer guys.

 

Wow, I didn't know a '90s Porsche would do that too, I'm on my 2nd early '80's VW Scirocco that will only run well w/ the 02 unplugged. I've changed 02 sensors w/ no effect. In my case I believe it must be 'the brain', but it runs very well, gets good mileage and passes emissions so I leave it alone.