What kind of Octane do you put in your C-Class?
I recall the owner's manual says you can use lower octane in an emergency... put in only the amount needed to get to a source of better octane, and fill-up with premium asap. It doesn't get any clearer than this.
You bought the car knowing it took premium (I hope) so don't go back on your commitment and feed it junk gas. Just realize you're getting much better mileage than that 4-ton SUV parked next to you at the light and move on down the road with a smile.
In addition to potential Pinging problems, there was a rash of posts several months ago from folks using 87 octane. These members were complaining of receiving fault codes from the car, in addition to sluggish performance. I recall the conclusion was you get fault codes with contaminants in the gas (water), or low octane gas.
My manual says to use 91 octane, but where I live 93, 89 and 87 are sold, so 93 is what I use.
I accidentally refilled my half tank with 89 rating gas from an Exxon station. It didn't seem to have had any affect on the engine performance at all.
I wonder if 89 is OK ( here in Va there is no 91 rating or at least I don't recall ever seeing one) or it's the half & half formula that equated to the MB required gas rating.
Peace
The Best of Mercedes & AMG
There have been several threads previously concerning the (nasty) results of running less than Premium fuel in these cars. You should only use 89 octane in an emergency, adding Premium at the earliest opportunity. It's all in the manual.
Today, it was 40 degrees F .. no problemo..as it should be !
However, the service writer simply said "bad coil".
If a coil "goes bad", it may only affect starting, or it may not work at all. It depends, I guess, on the extent of the damage. But, in any event, there should be a misfiring code thrown, and although it doesn't show on the MFD, it gets stored in the ECU's memory. Your dealer will see it in the Star system.
Mr. Bob, I bought the car at Plaza and would really rather have it serviced there but they do not have weekend service so I need to take a day of vacation to get to St. Louis. I will do it though. I'll still use 91 octane gas but I may try a different brand to see if that helps.
If there are two dealers, my thought was not to drive to St. L, but to call Plaza by phone and ask their service dept about the (suspect) advice you're getting in Columbia. If they confirm that the advice is bogus, I would definitely tell your local dealer in Columbia of the St. Louis advice and make them fix it locally. As others have posted here, I suspect you have a coil, or other problem not related to gas usage..
Otherwise, you'll take a vacation day trip to St. Louis, only to find (surprise) that they'll want the car overnight (or for two days) and give you a loaner, meaning another vacation day to retrieve your car. That will get old quickly.


