Help with Intake on 08 E320 Bluetec

[mdelfunt]

Hey guys, I've been having some issues over the past 6 months on my 08 E320. It's been going into Limp mode regular. I've resolved much of it but there are still issues. Codes I've been getting were EGR and downstream O2 related. I replaced the O2 sensor and cured that problem. EGR codes were 2355-001 (EGR recirc air too low) 2598-001(Y27/9 EGR signal position signal fault). I recently changed the EGR but still getting 2355-001 - although it doesn't appear to be going into Limp mode anymore.

From a performance perspective, it seems to be using a lot of fuel and its sluggish on acceleration. At times on takeoff, the engine appears to stumble and drop RPM's quickly but then recovers - giving a jerk in the car. The Turbo appears to be working OK and there are no other codes other than one glow plug.

The old EGR was not very dirty and was opening/closing ok but the feedback signal was apparently not working. To my knowledge the EGR was original.
I've been asking myself if I should remove the Intake Manifolds and clean everything up - assuming its gunked up.
1) I be curious of others thoughts on the above and
2) Can anyone share removal instructions on Intake?
3) What's the best way to glean the Intakes?
4) What parts should I absolute replace during the project?

Thanks guys!
Mark