I have a weird issue with performance, and just wondering if it is related to the O2 sensor (which I know is faulty).

After the car is warmed up, I noticed that it suddenly feels like the turbo isn't working anymore. This usually happens after I've been driving for 15 minutes and stop, then start the car. Sometimes it happens while I'm driving - but if the car is cold, it always runs normally on start.

The symptoms can only be described as going from a turbo powered acceleration cruising, to a ****ty, cheap little 4 cylinder without a turbo (no power at all and the engine sounds different).

Any ideas?

 

I guess what I'm trying to ascertain here is whether forking out $$$ on the O2 sensor is worth it, if for instance, there's a bigger problem (like the turbo failing) - in which case, it might be better to take the car to the tip.