#1--I thinkl they cleaned the Injectors--you do not need to have the
injectors cleaned ever, as long as you use good gas.  Chevron makes Techron
and valvoloine and others make gas similar additives that will clean the
injectors, the intake valves, and the top of the pistons, and perhaps a bit
on the head as well at $8-10 a bottle.

It's just because we are into giving the cars the best that we even need to
use the additives--but I do it 2-3 times a year.

Use good name brand gas and you do not need to clean the injectors, unless
you want to support the dealer.

The noise at start-up COULD but is unlikely to be injectors, more likely
valve train

Is the oil in the 'safe' zone
are you using 5w-30 weight oil
I forgot if the CL has hydraulic valves--if it is mechanical--which I do not
think it is--you need to get them adjusted every now and then--30K miles or
so.

Best luck, and drive gently from a cold start--do not warm it up--start it
and drive gently--accelerate easy--its fine to drive it 60-70 and it will
warm up in 2 miles when cold, but no more then 1/4-1/3 throttle when cold!