New to forum 2014 RR Sport HSE 90,000 miles

[jlglr4]

I’m not sure about the duration (45 seconds), but 1100-1200 at startup dropping to 600-900 after a short period sounds about right to me. 2800 at start up sounds high, but I’ll try to take note of what my engine does on startup and post back.

The duration of high idle on startup I believe is based on input from a temp sensor (thinking it’s the catalyst temp sensor, but not sure). So, if the engine is running really fast at startup (2800), that probably reduces the high idle duration.

Was the PCV diaphragm you removed torn? You mentioned that replacing it brought the idle rate down, but did it fix the rough cold idle?

 

[KH 2014 RR Sport]

I’m not sure about the duration (45 seconds), but 1100-1200 at startup dropping to 600-900 after a short period sounds about right to me. 2800 at start up sounds high, but I’ll try to take note of what my engine does on startup and post back.

The duration of high idle on startup I believe is based on input from a temp sensor (thinking it’s the catalyst temp sensor, but not sure). So, if the engine is running really fast at startup (2800), that probably reduces the high idle duration.

Was the PCV diaphragm you removed torn? You mentioned that replacing it brought the idle rate down, but did it fix the rough cold idle?

 

[KH 2014 RR Sport]

Yes it brought the rough cold start idle down to 1,100rpm after PCV replacement. Actually the first time I cold started after replacing PCV it went to 2,800. But very time after that one m- for the last 5 days or so on cold start it’s at about 1,100-1200 rpm then down to 900rpm after 45 sec

 

[jlglr4]

That sounds normal to me. When I first started today, it revs at 1100-1200 for maybe 30 seconds, then drops to 900. It was probably 80 degrees in the garage at the time. You might have had a bad PCV and slightly lean condition for quite a while causing higher RPMs at start, and it just recently got worse causing the rough idle.

You could have autozone check for the code again, or have your fuel trims checked at the shop - would tell you whether you still have a lean condition at all. Otherwise, I think you’re probably good.