Short answer: No

Medium answer: No, it is drive-by-wire, so no physical adjustments on the IP.

Long answer: Yes, if you install an IP from a 603, then you can adjust the idle. ( that is also the sarcastic smart ass answer, but I have done that.)

You are stuck with finding and fixing the problem. It is most likely air in the fuel lines. There are many points of failure on that car's fuel system. Every fitting has o-rings, the pre-filter has an problematic o-ring, there is an o-ring on the back of the fuel control unit. You can try to find which one is leaking, or you can just replace them all and be done with it for a few years.

__________________
Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO