97 e320 "gags" on hard exceleration

Like when your jumping out into traffic for example and you press the accelerator to the floor, the car just ~floods out~ (bogs down, starts to stall, hesitates, chokes = gags). A slow steady pressure on the gas pedal
results in (the expected) strong acceleration.
Hard acceleration at higher speeds (55-85) has the same symptom.
Anyone have any idea's? (yes I will be bringing it to a dealer, just kinda wanted to walk in with my eyes wide open).
TIA Ken
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Insufficient fuel for the sudden throttle opening, the task is to learn why.
Could be the air mass sensor, poor fuel pressure or dirty fuel filter.
I own the same model so please post what's found to be the cause.
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9 times out of 10 this is caused by the air mass sensor.

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I had the exact same symptoms with my 1997 E320. The solution was diagnosed by my mechanic while doing some maintenance and he suggested I might want to do it myself. It turned out to be the Air Mass Meter which is located between the air inlet in the grill and the intake. It's a 10-minute change of components that I did myself (hose clamps and a plug). It lists at Mercedes for around $370 but I bought it at my local MBZ parts house (Euromeister in Castro Valley, CA) for about $170. Good Luck.
Ken Bleau wrote:

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Thanks for your Kind reply, someone else indicated it was probably the Mass air meter as well. I found it online for about retail ($350+), and will call around to see if there is a better price locally.
By the way, did your gas mileage go to crap as well?

kinda
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Give Phil at www.mercedeshop.com a call (Fast Lane). OEM product, awesome price.
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My 98 E3290 w/ 61,000 goes into the independent garage on Tuesday, 13-Jan. for many of the same symptoms -- bad to the floor acceleration, running a tad rough during even moderate acceleration..
Additionally, its showing error codes for both O2 sensor banks.
I'll post the outcome.
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Thanks for those that posted reply's . It was the Mass Air Meter (Sensor) . 5 min to change, will the check engine light go out or do I need to disconect the battery for a "re-set"?

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The ECU fuel trim adaptation memory will come back to normal as you drive the car through approx. 40 drive cycles . Clearing the memory with a scanner is he preferred way, as that brings the base line back immediately . This will prevent other fault codes from triggering in the interm . and will also verify there are no other codes stored...but ECU relearn through drive cycles will work..
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A drive cycle would be ... full engine start/drive/engine shutoff? So that 40 cycles would be 20 days of twice a day drives?
On a "Check Engine" thing that happened, the dealer said it takes something like eight recycles to clear the error, but I wasn't sure what constituted a cycle. I think he said something like the engine cooling down a certain length of time between restarts, like overnight. I'd be interested to understand what triggers the ECU storage.
Thanks!

cycles .

the
through
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Technically, a drive cycle is only after the ECU has gione through ALL it self-Test proceedures.. this requires driving , steering, breaking, warming up sensors, shifting,etc... so, it can take quite some time.. However, the CE lamp memory usually [ depending on chassis] takes 40 cycles of key/engine on/off.. The CE lamp memory and the fuel trim adaptation memory are different , so resetting a CE lamp does not clear or reset fuel trim memory.. that is re-learned by driving and if the trim adaptation % does not come back to normal parameters, the CE will trip again. That is why it is best to reset both with a scanner...
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Thanks for the explanation. I overfilled the gas tank awhile back (the nozzle had a defective handle trigger). For the rest of that day, the car ran like two cylinders were missing. The following morning, it ran better, but seemed to lack power; it felt like it was stuck in third gear and the ECU was adjusted wrong. As the weeks went on, it returned to normal, quick and responsive. I always assumed the ECU was instant on, instant off adjustments, instead of accumulating codes and readjusting over time. Makes sense now.
Thanks for the information.

,
cycles
normal
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So what if the CE light trips.... and then goes off, storing the error codes to memory. Does that mean the system has determined that whatever condition triggered the code no longer exists? Or will the CE reappear over time unless the error codes are removed from memory or the error it detected is repairs?

driving
so
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It seems like the Check Engine light came on immediately after sensing a problem with an overfilled gas tank (doused charcoal cannister), but took many recycles of the car (temp, start/stop, self-tests, whatever), to determine that it was an isolated incident and not chronic. The CE light being on was stored in the fault memory, but the Check Engine light and ECU began readjusting as soon as the problem resolved itself. It seemed to be more that the error had been corrected, and it slowly figured that out. It did store an error in the fault memory, but still readapted to the gas tank overfill being resolved. It was back to normal in a few weeks; the CE light only stayed lit for a half-day; the fault memory was still stored in the computer; the CE light never came on again.

,
to
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Thanks for your reply, the Check Engine light went off after about 2 day's (or 8 Start -> Drive -> Stop -OR- 180 miles)

,
cycles
normal
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