rondocap

So yesterday I went to some gas station in NJ, and put in some gas. I always put 93, but in NJ they put it for you, so it is possible the guy put in 87 or 89, and not 93 if he misheard me.

Anyway, I'm driving a few hours later, and I'm accelerating here and there in the usual AMG fashion. ( )

So..after I accelerated on the highway from maybe 40mph to 65mph with the kickdown, I noticed something very odd. I had no more power from the accelerator pedal. It didn't stall and was still going, but wouldn't accelerate more. So I pull over at an exit, and turn the car off, put it in park, and start again. OK, so now it's accelerating again, but it's still a bit funny. So I give it a little push...and the check engine light comes on. The Throttle response is much worse.

I think to myself, hm - what could it be? Then I remember reading about bad gas and how it can cause bad performance or bad throttle response. I pull into a gas station that I know and put in some 93. The check engine light immediately turned off, and the car was back to normal throttle response.

That's strange - so was it really just bad gas that caused this? The check engine light went out immediately after I put 93 gas in, without me even driving it. Is it just bad gas, or could I have something that is failing, like the MAF sensor, or something like that?

Car has 124k miles for reference. Thanks!

tgoss

Either that or your cap wasn't completely tight. Excess vacuum can throw a CEL and pull timing or what not to save your motor.

blackbenzz

+1. Read the codes to see if you have any stored codes to be safe

Thericker

Did you recently purchase a new tune?

rondocap

Heh, no new tune it's stock. But now that you mention it...maybe I need to do that too.

If a CEL light goes off, is it possible that there are stored codes that still may indicate some issue in the car even if it is no longer on?

rondocap

Update: Actually I was wrong, I test drove the car more and here is what I am getting:

Check engine light is off, but something is really strange. When on park, the car revs higher pitched than normal, like it's strained. When you turn it on, it's the same thing..higher pitched whine that wasn't there before.

When driving, low rpms it is OK, but there is no power really, like if I accelerate. I checked with a scanner, and I got these codes:

P0700 - (Transmission control module, says TCM has detected emissions related fault)
P0120 - Throttle position sensor
P0500 Vehicle speed sensor - I recently had the ABS speed sensor for the right wheel changed, is this possibly it and the code was just not reset? So this code probably isn't it.

So is the throttle position sensor the most likely cause? It's really strange, anyone had these problems before?

Hammer Down

Check with the dealership, I believe that there was a campaign for the throttle position sensor a few years back. I had a 2001 S55 and I think I took it in for something like that. Good Luck

wizos6

What IC pump do you have and when was the last time you changed it? I would say also you might want to disconnect you battery for 45 min's to see if that helps with your TCU.
Seems like power related issues stem to shut down of supercharger or overheating usually but the check engine lights probably mean that your local dealer is going to have to check it for you....Good luck!

Cory @ Kleemann

These cars don't have MAF sensors- speed density=IAT and MAP sensor.

There isn't a throttle position sensor per-se- these throttles use a feedback circuit within the throttle actuator to determine position. Sounds like it's time for a $1000 throttle slide to me- it's not a super common failure, but it does happen.

gikky1

Hey Cory I had the exact same problem as rondo, And when I called the dealership they said the 03 s55's don't have the throttle position sensors like u said, they said they have electric gas actuator but that's 1270$ and I don't have warranty... Do you think there's a cheaper way or maybe something I can do on my own?

desired_speeds

there's a hose underneath your throttle body that may have come loose.

gikky1

sorry im kind of a noob with benzes but where is the throttle body located ? thanks

desired_speeds

its what the airbox Y pipe connects to at the center at the very back of the engine. remove the airboxes and y pipe for better access to take a good hard look underneath the throttle body. You may have to stick your hand in there and feel around.

AaronZ'sE63

Rondo- I know exactly what your issue is. This was happening on mine just two months ago. Exact same symptoms. whats essentially happening is your transmission is staying in overdrive and not shifting down, which is why you have no power but the car still moves. I took it to the dealer and they advised that I had a bad transmission plate. They'll have to flush the transmission and do some recalibration as well. The whole job is about $1700 unfortunately.

theunderlord

I heart 2 year old threads. That is all. Carry on.