2008 XKR Coupe 60k miles.

I got a couple of codes recently. RPM's surge between 500 and 800 at idle. Battery was original so I got a new one and codes came back after a few trips. I found P0128 and will be getting a thermostat. But a search for P050B turns up nothing. Google it and I find a link for a 2006 XKR with TSB 30313 says ECM needs a re-flash. It's the same symptom but there's no reference connecting it to a 2008.

 

It's not likely to be false.

 

Did you ever diagnose the P050B code?

 

I am sure the code is P0508. That would be idle air control valve.

 

The P050B is cold start performance which is what I got this morning. And I do remember a TSB for it on other models so I'm wondering if the OP solved that.

 

Me too any ideas anyone? Didnt do it until dead battery...

 

I haven't had that code since winter. I think it's tied to the P0101 i'm getting due to a vacuum leak. It makes sense ... at colder temps, the air is more dense so a vacuum leak would be most noticeable during cold starts. That's probably what triggered the P050B. Still waiting on a smoke machine to find the actual source of my vacuum leak.