ajg617

After the recent misfires on cold start, I pulled the plugs on the 3.0 to have a look. Clean as a whistle but with a whitish-gray powdery coating on them that didn't tend to rub off. Kind of makes me think it is running lean but no codes except for the usual CAT codes.

Airbag

Did you replaced the cts already?

jcman

What brand oil are using?

ajg617

No. Just curious, does that affect interior heat flow in any way? Temp gauge is rock steady.

ajg617

Always synthetic. When I change it, usually Castrol. Audi offers $69 oil change specials and the last one they did they also put Castrol in. When my indy does it, I'm not quite sure what he uses but I think it is Pentosin.

SloopJohnB@mac.com

More than one coolant temp sensor..the one he's talking about tells the ecu the engine temperature which affects the fuel injection map picks and starting scenario as well as warm/hot engine fuel management. Separate temp sensors for the instrument panel temp gauge and ecu input.

SloopJohnB@mac.com

Dunno what kind of synthetic they can afford to put in for $69 with a $15-20 Mann oil filter on a V8…
One time I put my car in for a scheduled oil change (warranty) with my preferred Amsoil 15W-40 and when I got the car back the oil was still in the back of the car. They said they put Mobil 1 in but hard to verify. I made them change it while I watched.

jcman

Our 4 wire CTS has two thermistors in one, one pair is a ohm value is for the ECU and the other pair is for the temp gauge.

ajg617

Yeah, I don't know how they can change it for that price either though for the last year or more VIP has been selling a gallon of Castrol full synthetic for 24.99. Everything else is over $30 a gallon. Even with the V6, I still take close to 7 quarts with filter. (I do check the oil color when I get it back and they are putting something new in).

I used to use 10W-30 Amsoil and an Amsoil filter in my Cummins. 20K filter change and new oil every couple of years between tests. Loved it. Bet it's not on Audi's approved list.

ajg617

Haven't changed any. But wouldn't a lean (or rich for that matter) mixture throw a code?