My car was in today at the dealer with a list of things to check because the CPO warranty is up in a month. I mentioned that the car was sometimes idling rough and knocking/ticking soon after start - despite the cylinder head being replaced a year ago. Its no where near as bad as it was, but it still does it on occasion - especially when the temp swings from cold to warm (ie - first hot day after winter). The revs also sometimes bounce around at idle for the first couple minutes. It appears like the computer is preventing a stall or something. When the engine warms up after being driven for a bit things smooth out.
The SA called me back and said they didn't come up with anything to explain this, but suggested that I might try the dealer "fuel injector cleaning service" for $199. Its not part of the CBS schedule, but he said they sometimes recommend it for higher mileage cars. Mine has 70k.
Does anyone know what this is? Is it any different than just running a couple of bottles of techron through the car? If so, how so? Is this likely to solve my issue?
I did find:
Fuel System Cleaning SIB 13 01 07.pdf
And also this, which (I think) describes the procedure further down in the document:
B130107Procedure_A,B,C,D
thanks