Engine problems, yellow light on , help please?
 

My 09 with 23K mls during day time temperatures in winter time in Houston between 50-70 degr F, the few rare days in the season in Houston you can actually give your AC a rest, always starts up well , with the great bark to start off. Having said that, during these days and I am not sure if there is a relation between AC running or not, with the AC turned OFF after the engine is warmed up and you slow down at a traffic light or start up after running an errand, the idle is always very rough, and getting worse. sometimes I hear it runs on only 5or 6 cylinders , almost shutting off until I give it a little throttle, hackles and puffs comes back to live most of the time. The yellow light blinking. This morning it started up ok but the yellow light is now solid. Going to drop it off this afternoon. Oil level is fine. I always treat the car with respect, slow warm up an only gun it for some fun occasionally when and where possible and only if the engine oil is 16oF and up.
Any ideas or suggestions?
Thanks!

Tuned?

Sounds like misfires or cats to me. Reading codes will help.

Yes Eurocharged

Could be related. However, only way to really diagnose anything is with what engine codes you have.

Still sounds like misfires/intake/cat issue

Off - topic but I feel like the newer/face lifted models have an easier time accepting tunes. I have an 09 as well, but when I run it with a tune it isn't always perfect. Just a thought.

It's at the dealer. Indeed the codes will tell the story I hope. My service tech told me I should not be concerned that anything major is wrong as these engines are very reliable and he has not seen major issues on these engines. I am still under warranty as well.
Will keep you posted about any news on this.

my CEL stays on now...i have 2nd cat delete and CF boxes and a eurocharge tune...the dealer says nothing is wrong with the car ..it's just having the 2nd cats gone thats throwing CEL but other then that theres no issues.

I have cf boxes and 2nd cat delete and also EC tune my cel doesnt come on. Mine is a 09 btw

what dealer in htown do u go to? let me know if they are tune/mods friendly..

This is interesting. We all have an Eurocharged tune with a cel. P0171 for me. Got it right after v4 was installed, I just keep clearing it. Lean bank1 which is definately related to the tune because when I had the v3 tune almost every time I dove it I would have to clean the exhaust tips when I returned home. Now I don't have to clean them AT ALL.
To lazy to send the ECU back. But may have to at some point. Thoughts?

yeah mines tune related too..lean bank 1...the dealer said it's nothing to worry about...i asked jerry and he said to leave the battery unplugged over night and it fixes it so im going to try it tonight, btw do you have a reader? if so which one? ive been curious what ones work, the dealer here uses some MAC tools one for a handheld

change your oxy sensor and the code will disappear
I just done mine and im code free

oxygen sensor? the dealer isn't getting any codes for that though? wouldn't they be able to tell?

lean bank 1 is the oxy sensor bud :)

I just brought one costs 200 problem fixed

can't buy online? is it pretty easy to install?

go on ebay thats where i purchased my from

http://www.ebay.com/itm/Bosch-17016-Oxygen-Sensor-/111168218738?pt=Motors_Car_Truck_Parts_Accessories&hash=item19e2246672&vxp=mtr

:y right on the money!

i had taken my charcoal filters out and i kept getting that code. i put them back and i havent gotten it since.i have a tune,LTH,no cats, and dry filters.suxs when the CEL is on

Having the 2nd cat delete doesn't throw a CEL.

I wouldn't say this code means necessarily faulty O2 sensor. This is one of the probable causes but there are other scenario that could throw this CEL (faulty/dirty MAF, vacuum leak are among the most common). In your case the O2 sensor was the fault.

I had the lean bank cel spoke to a Mercedes mech told me to change out the oxy code gone

But yes you are correct there are multiply reason why this cel can come up

Got one from Harbor Freight, not the cheapy one though.

Skeptical on the oxy sensor since mine came on right after the tune upgrade...coincidence I don't think so.

Will try the battery disconnect this weekend.

I am eurocharged with k&n filters and have had absolutely no issues whatsoever, not a single hiccup... KNOCK ON WOOD!
I did the charcoal delete and about passed out in my garage from the fumes, that and it actually changed the sound of the exhaust note a bit so I put them back in. I have never thrown a cel.
I have 43k miles on my car with about 500 miles on the tune.
How many miles are your cars, and how many of those miles are with tune?

Hi All, MB Greenway Plaza is where I always go and they have always been very cooperative. They believe it was the fuel pump which was replaced under warranty. Car is running fine now.
Thanks for all the responses!

Charcoal delete always gave me CEL. Now I just leave them in.