hate to say this,but I cannot believe you went to all this trouble without actually checking the pressure. had the same problem with my Jeep. Went to a mech and for $20 he confirmed in 15 minutes my pressure was fine, just my gauge was off. his fix-turned the needle on the gauge to where it should be.

Have a mechanic check the pressure. Also, isn't 0.3 at idle normal for this MB???

__________________
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"