Check engine light, bad gas and power loss?
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!
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!
Last edited by Jud Chapin; Mar 18, 2010 at 03:13 PM.
I'll let you guys know if the problem returns and how it is running in the next few days. I did open the gas cap and close it again the first time I pulled over quickly, but the light stayed on, it only went off after I put some 93 gas in the car. Maybe it needed a little more "breathing" space for the vacuum or pressure to be released.
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If you ever notice a gas truck filling the underground barrels at a gas station, they fill from the same truck tank. They just (supposedly) pour an octane enhancer / additive package in the "high octane" storage tanks. (And I bet sometimes they dont even do that.)
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Every gas station has two tanks, and a mixing valve (sometimes connected to a third tank), to create midgrade (89 here in California). There are ALWAYS two trucks, and California weights and measures requires that 91 be trucked seperately from 87. Period- there are hellacious fines for unmetered mixing, and tests are conducted very often for octane rating of each tank, as well as the output of the mixed midgrade. I'm not saying one brand is better than another, but trust me, most states regulate the hell out of delivered gas, and there are a lot of different regulatory agencies that monitor octane, pump volumetric output, price multiplier factor and cash / credit discount schemes. You are very well protected in this arena.
I'm not going to weigh in on the "which gas to use", since the owners manual clearly requires 91+. But, it's your car. I HAD to put in half a tank at Lake Arrowhead once (its all they had), and the car ran like crap all the way to the basin. Filled up with El Cheapo Arco 91, and no more problems. I'm sold on 91.
As far as "adding additives"? Illegal- The gasoline that arrives by distributer is pre-additized, and only comes in two flavors- 91 and 87. Federal law requires that any additive, like MBTE be clearly disclosed (ands its illegal in California, now anyway...) on the pump.
Chris
Last edited by socalsounds; Mar 18, 2010 at 08:22 PM.
I only see one truck come at a time, so the other truck with the different grade must come at another time if they must be trucked separately. I have never seen two trucks at a gas station, ever.
Last edited by tusabes; Mar 18, 2010 at 10:25 PM.
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?
Chris
I'm hoping it's just the throttle sensor, that seems like a fairly cheap fix.
When I put it in park, it's really funny - like it is an unstable rev. It goes up a little and down, doesn't stay still.
Anyway I'm going to get it to a shop soon to get it completely figured out, but thank you guys - keep the ideas coming as I like to know what may be going on! I
ll keep you guys updated.
I have never seen any car so dependent and so senstive on a fully charged battery to run properly than a w220. Other cars you can have a completely dead battery, jump it and drive off. These w220 cars get damaged if you jump them, get all kinds of errors if the battery is just low, etc.
Just my two cents.
Pedal Value Sensor, short circuit at signal path 1
Component n15/3 (ETC control module) memory is fault)
No CAN message vehicle speed signal left rear wheel from control module
So maybe it just looks like it may be the throttle sensor or something to do with the pedal. The car is sounding a bit different, a bit more strained - especially when I put it in park the idle is not consistent as before. I've been driving it at low rpms and it drives fine, but I don't want to do the kickdown as that caused the loss of power and check engine light before, so I figure it will do it again.
I'll keep you guys updated - hopefully it's not an expensive fix.
Its not about the price difference, all modern cars compensate for lower octane gas. They dont start running badly. I just cant believe all these tall tales of using regular gas and actually experiencing a noticeable effect in how the car runs.
to see what they find. I'll keep you guys posted.m







