Car stalling when hot and running rich...

[bmwnoy]

Car idle fine but stall at times when hot, but runs good on the higway.

And car is running rich...

Could it be the plugs, o2 sensors, wire, ??

What should I change out first...??

[jlevie]

The O2 sensor is a maintenance item with a useful life of not more than 100k. If that applies it needs to be replaced.

What makes you think that the engine is running rich? Unless you have data from an EGA showing a rich condition this is possibly a guess. Given the symptoms my first suspicion would be an intake leak.

[Adiabatic]

From the limited information I'd say first backprobe your ECT sensor. If it's idling fine but stalling when hot it may still be in warmup mode due to a bad ECT stuck on a low value. It would also explain the general rich problem, but unless you're spewing black particulate out your tailpipe I'm not sure exactly how you would distinguish rich from lean.

Before I start the diagnostics process, though, I always check ignition connections (wires, plugs, coil) If anything the porcelain electrode on the plug will tell you a lot of info on whats's going on.

If nothing is wrong with the ignition, I'd check fuel pressure. If nothing is wrong with fuel pressure, start looking into diagnostics and relay this information to us so we can guide you further.

[bmwnoy]

Just changed out the plugs, wire still looked new. Clean out the MAF with cleaner....planning to change out the o2 sensor next.