My CEL and P0170 turned out to be the MAF. I was told by a dealer tech that codes in that range are almost always the MAF. I was told by a friend, before I replaced the MAF that I might have a vacuum leak so you might be on to something.

Also some people claim that K&N air filters can foul a MAF but the jury is still out on that. But I think I would clean the MAF with some CRC MAF cleaner and replace the K&N with OE.

 

I have also been told to install a bosch maf.I put an autozone maf on mine and it only worked for a little bit before crapping out again.

 

Your codes are defined as running lean on both banks. This is usually due to fuel starvation or unmetered air. If you're running K and N filters, the hrow the K & N anway, replace the MAF with a factory unit (Auto Zone and the like sell crap),clear the codes and you'll be good. You MIGHT be able to salvage the new MAF by cleaning it with brake clean and blowing it off with air. If it was a aftermarket unit, I'd just toss it out.

 

I replaced the TB to Elbow rubber seal and reset the mixture adaption. So far 100 miles with out the code coming back on, all monitors are ready except for the evap, I've tried to complete the drive cycle twice.

The old seal was starting to get hard and would crack a bit when you bend it. I would say its safe to assume when your pcv hoses start getting brittle you can expect this seal to start going bad also.

 

I hope the solved it. You didn't say what type of MAF you used and I assumed you used the proper Bosch part. That's what I did and that was the end of the error code.

 

The maf I purchased was a rebuilt Bosch from rock auto $150.
After 300 miles the codes have came back on.

I noticed my intake manifold pressure sensor is reading 318 hpa at idle which I believe should be a negitive number, when the engine is reved the number doesn't drop below 200s. Maybe I'll try swapping pressure sensors. What is your IPS reading at idle?

For future search purposes my iPad scanner shows these codes as P0170 & P0173 where as my sds shows P0171 & p0174

Also to add to the parts replaced list is:
#6 OE maf rubber seal and TB rubber seal

 

I scanned the IPS on my E320, the readings are about the same but the E320 range for this sensor is less than 500 hpa vs my S55 shows the range should be less than 0. Kinda strange but o well. I think I'll have to buy a smoke machine now.

 

So, codes are coming back ? Have you cleaned/replaced the maf, and kicked the K&N to the curb ?

 

All the parts listed were recently replaced in order to fix these codes, the MAF is a new bosch rebuilt from rock auto $150.00 so I don't think there is any need to clean it. It must be a vacuum leak some where I can't find. I think I'll buy the OTC 6522 smoke machine tonight.

 

Smoke machine is pushing smoke out the egr vent. Is this normal when no vacuum is applied to the egr?

 

That should not be happening. It should not bleed smoke.

 

I put some duct tape over the 3 ports. The CEL went off after 3 short drives with all monitors set. A new EGR should be the final solution.