I have a 2006 Mercedes E350 with 97,000 miles. I have put new spark plugs in but still have misfires in two cyl. Car ran smooth with check engine light staying on. Show PO 171 B System too lean bank 1, PO 174 B System too lean bank 2. Recently the car has started running rough with the same above codes & 2 misfire codes PO 303 & PO 304B. Car also idles high sometime when car is in park. When driving i take the pedal car but it feel like the car is maintaining speed unless i brake. Once I brake rpm will drop. Recheck sparg spugs that are ok not sure if coil backs are bad or if it is something else.

Any help would be greatly appreciated. Thanks

Dave
deforney@***.net
602-790-3597