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2002 E320 Sport
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Discussion Starter · #1 ·
I have about 38k miles on my 2002 e320 and I'm experiencing an intermittent rough idle during a stop. It would also hesitate when I press on the accelerator. The rpm would drop down which causes a mild shake on the car and steering wheel then, after about 20 seconds, it goes back to normal on its own. I won't experience it again until later in the day or a few days later. I get no codes on the dash or even when I plug my OBD2 scanner.
I can't imagine I'm due up for spark plug/coil/wire change with low mileage. Any advice on where I should start?
 

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'01-E320 & 02-ST2
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That low a mileage suggests lots of short trips, I'm sort of leaning towards a dirty EGR valve/tube.

I'd probably run a couple of tanks with Seafoam added, if that did not help any at all I'd be back looking at the EGR.

Take care and enjoy the ride,
Greg
 

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1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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Also a symptom of a dirty MAF..

I would say dirty gas, and possibly a dirty MAF.

I am not a Sea Foam guy (although many have great things to say), I would add a quality injector cleaner and go thru a couple of tanks, put in a fresh OE air filter, and while replacing the air filter I would buy a can of CRC MAF spray cleaner and give the MAF a good cleaning.
 

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2002 E320 Sport
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Discussion Starter · #6 ·
You're right greg, I mainly drive it to and from work which is about 20 mi each way. I used to add a bottle of that Chevron fuel injector cleaner when I fill up approx every 3-4 months. I always get my premium gas from respectable brand ie Shell/Chevron. I'll check the EGR valve. Shouldn't a defective valve show a code?
I think I also saw a DIY for cleaning the MAF sensor. Although there I also read some threads about having issues after cleaning it. I just need to buy the torx driver this weekend.
Thanks all. I'll give them a try. I just hope to catch a small problem before it gets big.
 

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Cam, I can't recall. Did you say you checked for codes, or just no CEL? Codes can be present without CEL so it is always worth checking.

EGR does not seem to reliably throw a code unless it fails, much like MAF. You can clean it per the excellent DIY (and it is a special security torx, not a normal security torx, so you may have trouble finding it, I opted for pliers as mentioned in the DIY), but MAFs tend to be a recurring issue, particularly when dirty, not an intermittent one.

Changing the fuel filter is not a bad idea, you're at low miles but there are time and fuel degradation factors to consider.

Do the simple, basic and inexpensive things first, if it persists thereafter have it put on a scope so they can isolate it before you go broke/crazy chasing it.

Take care and enjoy the ride,
Greg
 

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2002 E320 Sport
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Discussion Starter · #8 ·
I don't get a msg on my dash. I also don't get any code when I connect my OBD2 scanner. What does CEL stand for?
I thought about the fuel filter. I just checked AutohausAZ and they have it for about $35. (I'll buy it with my cabin filter to get free shipping =)
Thanks.
 

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I don't get a msg on my dash. I also don't get any code when I connect my OBD2 scanner. What does CEL stand for?
I thought about the fuel filter. I just checked AutohausAZ and they have it for about $35. (I'll buy it with my cabin filter to get free shipping =)
Thanks.
Sorry I was on a smartphone with the last post, so I couldn't see that you'd gotten no codes. CEL is the check engine light.

Your reader comes on normally when you plug it into the port, right? Just finds no codes?

But I'm puzzled. If you drive to work 20 miles each way that means you only drive it 135 days a year to accumulate that low mileage. That said, if you normally drive it 20 miles each time you start it up, that would lessen the odds of it being related to the EGR, I was picturing a bunch of short trips.

How long has this been going on? If it was just recently after a tank of gas that might be all it is.

If not, assuming your air filter is good, the fuel filter is easy to change, and adding Seafoam won't hurt anything. Walmart is the best price, you can run two cans in a full tank if you want. From there look at the other things on this thread.

And be sure to post back to follow up no matter what.

Take care and enjoy the ride,
Greg
 

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1998 e-320 2001 ml-320
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some times your intake manifold or throttle body can have a lot of crust build up. i would buy a can of cnc throttle body cleaner. it is 02 sensor safe and spray it the the throttle body. they have it at walmart. it would try that before i start changing parts.
 
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