..does the 300 have one? If not, what does it use as a compensator for cold engines?

Symptoms are pointing (me anyway) in that direction or possibly a temp sensor failing (a LOT cheaper fix)...

Search the forum - it's a common enough problem that its posted with the correct solution I'm sure...

Kevin

P.S. - search "cold start" and you'll most likely find the thread with your solution

__________________
"Dangerous with a wrench...and not smart enough to know it"

Stable (in order of acqusition):
'84 500SL, 280SEL (Euros)
'77 280SE. '90 560SEL
'79 450SEL 6.9,
'95 C280 (totalled by daughter 8/07)
'81 280SL (rescued) '88 300CE
'86 560SEC '95 C36
'01 CL55

DD's: '04 S500 4Matic (SWMBO)
'04 F150 Crew