Idle problem after cleaning EGR tube
 

I will try to give all the details of the problem...I removed the Intake manafold last night to remove the EGR tube because I had the EGR low flow code again on my C280 after having the dealer "fix" it about 2 years ago. (It was caked solid inside, must have not been cleaned well) In the process of removing the intake manafold the Breather Hose (P# 1040943582) cracked in 3 places, it was very brittle so I made a makeshift tube until the dealership is open and its been hooked back up however the problem is that now at idle the engine runs rough and the idle drops down to about 500RPM then it catches it. Anything above 800 RPM its very smooth. I have checked all the vacuum lines and dont see any problem. I'm wondering of the computer needs to re-learn its mixture at idle speed now that it has a clean EGR tube, or if my make-shift breather hose that is 1/2" tube is causing a problem when the original was 3/4". If anyone has any suggestions please let me know. It was running perfect before, with the EGR tube blocked. Its also not giving any codes that trigger the Check Engine light and I did replace the switch over valve and EGR valve when the original problem cropped up. Sorry for the long post, just providing all the details I can.

PS. For anyone cleaning an EGR Tube, using a throttle cable enclosre that is used on small lawnmowers with a power drill works like a charm.

Thanks and Happy Thanksgiving!

-Brad