Thanks 97dmsrS420.
I agree. We are all just trying to help others.

I totally agree about your rural petrol station scenario.
Here in the UK many rural stations are shutting down due to not being competetive with the supermarkets who have cornered the market. The problem is so bad that questions have even been asked in Parliament about the situation.

 

UPDATE: After a frustrating Saturday of cleaning the fuel tank and putting gas in the vehicle, the car ran great. We disconnected the battery and the CEL went out. It stayed out until I got in the car yesterday morning and drove to my parents house. I got on the highway and was traveling approximately 65 mph and the car was great. When I got off the exit and began braking, the CEL started blinking and the vehicle felt like it was going to stall. It runs fine while I am accelerating, but when I stop it feels like it is going to stall and it shakes uncontrollably. I finally gave in and took it to the Mercedes dealership. The service advisor told me that I need new motor mounts and new tranny mounts (?). Does this sound right? He said that is what came up when they checked the CEL code. I didn't think this could cause so many problems. When we drained the gas it was watered down and had debris floating around in it. Help!

 

Pardon me, but we seem to be chasing a rabbit. What were the fault codes? Unless we know the fault codes, what is wrong with your vehicle is anybody's guess. What you were told is highly suspect as being problem. So, unless we obtain DTC's on your vehicle any opinion would be "best guess." And I think that by now, you would be pretty much fed up with guessing.

I recommend you buy a code reader from your auto parts store.

 

Hi,
It appears that we have moved on from one problem to another. How did you eventually manage to get everything out of the tank?

As 97dsmtS420 states the key to diagnosing MB vehicles with the CEL "ON" are the Diagnostics Trouble Codes (DTC's.)

It is feasible that the CEL is coming on because the diagnostics system thinks there is a misfire due to the engine mounts being bad and allowing the engine to vibrate badly under certain conditions or similar. I am of course not familiar with all DTC's but would be extremely surprised if there is one which states "Replace Engine Mounts". DTC's are usually linked to measurable symptoms (rather than cause) like misfire (crank acceleration) or "Knock" noise level in cylinder block.....so I guess the garage have converted a DTC to a possible action required to resolve.

"Tes" your dealer (are they MB dealers??) by asking them what DTC caused the CEL to illuminate.
Incidentally is the CEL still illuminated??

If they can't tell you get them to repeat the test (they will charge a "small" amount for this due to the time required to carry out the test....15 mins or so on STAR DIAGNOSTICS (The MB system which is all encompassing)..... rather than a handheld DIY scanner. The later will suffice but they shouldn't charge for such a simple request. 2 mins tops. A good scanner is approx 150$ or so to buy then you can do the job yourself.

I'm also surprised about the flashing CEL. Did you mean it came on and then went OFF again after a fixed or random time base??
I may be wrong but I didn't think CEL's were supposed to flash therefore I conclude that the flashing time base must have been random suggesting an intermittent fault. i.e. the CEL did not flash regularly.

Can't help much more for the time being.

Stuart

 

After I was told from the MB dealership that the CEL was on due to the motor mounts and tranny mounts collapsing, then bad spark plugs (they were just changed about 10k miles ago), then bad spark plug wires-- the tech finally figured out that it was, indeed, bad gas. I told them this from the beginning, but they were completely skirting around that option. They are now going to drain the gas tank completely; clean the wires and tank; put another fuel filter on the car and re-fill it with gas. I am so mad because I told them from the very beginning that we really thought it was bad gas and they put all of this "extra" work into the car. Luckily, they did not do anything to the spark plugs and wires, but I am putting all of this money into a car that I really want to sell in a month or so. After all of this, I may just end up keeping it after all. =)