Mercedesamg5532

Hello everyone I have been having a proplem with my c55 for the past couple of weeks, when I start it up the idle goes up and down ( about 750 to 1000) this happens while I am in park or drive at a stop light. It also hesitates sometimes when pressing the gas at a stop light. Occasionally, it stalls when I come to a stop and shakes with the idle jumping up and down it feels like it wants to die when I come to a stop. After I'm at higher speeds it runs perfectly fine. Before I cleaned the throttle body and MAF it would stall on almost every single stop light or stop sign, after cleaning those two it still has all of the same symptoms but It just doesn't stall nearly as much as it does now. One of my friends which is a mecanic took a look at it and said it was the throttle body gasket. Has anyone had this problem or know what this could be?

CRod06

Try replacing the CPS.

Mercedesamg5532

Wouldn't that throw out a CEL

RenC55AMG

Not necessarily; mine was bad, didn't throw a CEL but you could pull it from codes. Cheap part, easy to replace (if you have smallish hands), and it's amazing how many little weird behaviors it'll fix.

insame1

Get the car scanned on star so you don't have to shotgun money at parts.

Mercedesamg5532

But my car cranks up just fine

Frederic944

don't guess, get a scan and get all the PCodes, only way to troubleshoot a vehicle, otherwise you can spend a lot of time and money without even have the guarantee to fix it.

RenC55AMG

Mine did too but acted weird at idle and at WOT; pulled codes, boom CPS.

insame1

It is way more likely to be the MAF than the CPS but you wont know for sure till you get a scan. Conjecture is just that.

Mercedesamg5532

The weird thing is that when the problem first started my car stalled at almost every stop and after I clean the throttle body and MAF. It's has only done it 3 or 4 times but it still idles weird and it hesitaties when I'm pressing the gas of a stop light. If I buy a new MAF do I have to re program it or anything or just simply replace the part.

insame1

No you don't but it may not be the MAF. FOR THE LAST TIME GET YOUR CAR SCANNED.

Mercedesamg5532

Not saying I was but I just wanted to know how if there's any reprogramming or do you just switch the part out with the new one?

Mercedesamg5532

And I alredy scanned my car and it was only a CEL from my secondary air injector.

C3Duece

unplug the MAF. It'll set a code for sure but if the car idles better than with it plugged in the MAF is failing.

insame1

So you own a star our das reader?

winks911

There are some hoses from under the maf to the rocker covers I had the same problem I eventually used some hose clamps to make sure I had a good seal.
Problem went away.

ItalianJoe1

Good call, very common for those PCV hoses to degrade on this engine and cause a big vacuum leak, which will cause the symptoms the OP is having.

Mercedesamg5532

Thanks for the advice.

Mercedesamg5532

Where can I get a star diagnostics I have only found a code and that was with a obd2 scanner.

Frederic944

At the dealer, also, maybe I'm wrong but I don't think what PCode you retrieved?

rrohtake

Hello All,

Happy Holidays!!!

I had the same problem, and in the process of changing CPS censor - hate how it's so hard to reach. While at it, I noticed the PCV hose connected from throttle body to engine had oil-like coming through, also going into the throttle body. My problem may be this oil-like thing sticking, as condition improves when the engine warms up. Do you have any insight as to what this may be and what it may mean? I'm worried if oil is being fed through, going into the TB and heading toward catastrophic situation.

Thank you.
Rick
2005 C55 with stock engine with Kleeman TCU and PSS9 shocks