My husband put in a tank of mid grade gas versus the premium. I have read the threads dealing with the octane issues, but I really need someone to tell me that I don't need to take the car to the dealership. It has the loss of power mentioned, which I hate. It has a slight shudder when stopped and idling. Honestly I feel like I could just smack my husband, he's a great guy, but dangit! By the way the car is a 2004 C230 kompressor sport sedan. I use it to run the kids around to their various activites and don't want it to conk out with my kids in the car and get stuck on the side of thr road. Thanks to anyone who can soothe me, or point me in the right direction.

READ YOUR MANUAL. It will tell you not to exceed certain rpms. However I think these instructions are for if you put in regular. My manual says to use 91 octane and around here premium is 92 and mid grade is 89 so I call 89 close enough. I was actually advise by my DEALER that I could run regular in mine and the CR is 10.5:1. But I don't have a Kompressor. I don't think it is a big issue but I would avoid drag racing.

MP

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Just go to a autoparts store and buy some octane booster and either make him drink it or put it the fuel tank. It will raise the octane and when you get below 1/2 tank just fill it up with what you want...Jim

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James A. Harris

I DID read the manual, thanks for the snarky comment. But I still wanted someone else to say it was okay. I just wanted some real world confirmation from some who may have been there. Octane boost was the first thing I told him to do. I'm glad to see someone else thought it was a good idea. Makes me feel better. As it is it seems to run worse when it is still 'cold'. My first instinct is to take it to the 'doctor'. But I hate to run the car in every time it 'sneezes'. I had a diesel Volkswagon Rabbit when I was a teen and a friend filled it up with regular gas. That poor car couldn't take it, I had to have it towed and they had to drain the tank and clean the injectors. It was a mess. I'm trying not to have flashbacks.

You are going to be allright. Just add the boost and fill up with high octane when you have a half tank. I have had the same problem before. Give him a kiss and hug and all is well....Jim

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James A. Harris

Sounds more like hot flashes to me.

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2007 C 230 Sport.

There's nothing to worry about unless you hear detonation (knocking or pinging sounds that you haven't heard before), especially when accelerating or climbing hills.

Modern cars have sensors that retard timing if the engine knocks, and most modern "premium fuel" cars can be operated without problem on lower octane fuels. They just might not feel as peppy because of the retarded timing.

Several of my friends switched their "premium fuel" engines to unleaded regular at my suggestion (I got tired of hearing them whine about the extra cost of premium fuel.), and they have not experienced any knock and can't tell any difference in performance or fuel economy. A boosted engine might have a more noticeable loss of pep than a naturally aspirated engine.

If you don't notice knock or any loss of performance, keep using midgrade or even try regular and see how that works.

Duke

Hot flashes! LOL!!

Actually my husband has no idea I was so peeved. He's a good guy so I kept my cool. Seriously, I would like to be the person who screws up my own car for once. It's always someone else toying with them, suspisciously always men. Come to think of it, mostly my brothers. Backyard mechanics, but they never have a running vehicle between them. Thanks for the help, I DO feel better now.





<~~~Gory ain't it?

Is somebody pullin' our leg??!

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2012 E350
2006 Callaway SC560

Not to be a smartass, but how much more truth can you get than from the company that built the car?? I take the word of my factory manual over anything anyone else tells me.........

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89 190E
2.6L
Arctic white
Grey leather
Sunroof
Pirelli P400 rubber
Smoked corners

My wife managed to put diesel in my Jaguar XJ6 once. Luckily only in one tank. (It had two tanks). Took a bit of effort to get the diesel out. She actually ran it through the motor on the highway too, then quickly switched the tanks back. I was FURIOUS! I mean, come on, that took real talent. The nozzel doesn't even fit in the tank fill neck.

I believe your car has a knock sensor, which should retard the timing and prevent detonation (knocks) before they happen. This is probably the reason why you don't think its running very well now, the motor retarded the ignition timing. I wouldn't think that going from 91 to 89 RON would make that big of a difference around town though. You know midgrade is simply a 50/50 mix of regular and premium.

My W124 300E does not have a knock sensor. My wife topped the tank off with over 3/4 of regular before a road trip. I drove to the autoparts store, added octane booster, then after I was down 1/2 tank filled up with premium. Never had any worries, and lesson re-learned, never let the wife fill up the car.

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On the plains of hesitation bleach the bones of countless millions who at the dawn of victory, sat down to wait, and waiting -- died

I have used regular gas in place of premium several times over the past couple years in my 300e. Usually on long trips where the stations don't have premium. I try to use as little regular as possible and top it up with premium again asap.

I have never had any rough idling or poor performance with regular gas so I wonder if your husband hs tinkered with something else under the hood...just kidding. I have never heard any pinging with the regular gas either so either the knock sensors or the engine soundproofing is doing a good job.

Oh My Gosh!! You are hosed!! The car will sputter and choke, head gasket will explore, and the cats will render useless and its gonna cost at least $10K to replace them

OK, I am just kidding. I actually run regular gas on my '87 300E for years and have no ill effects that I know of. It runs fine as long as I don't hot rod the 4-door old-geezer-mobile. Take it out for a long ride and burn off the gas if that worries you. Better yet, tell your hubby to do it. It will teach him a lesson if it conks out on the side the road in the middle of the night. Bet you he will read the label every time for the rest of his life when he pulls into a gas station.

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95 R129
04 Infiniti G35.5 BS
10 X204

I think your automobile will be O.K. Olive. It never harms to ask questions when in doubt.

I always put premium unleaded fuel into my Lexus LS 400, as recommended, so I cannot comment for sure on any damages that may occur, but I do not think it will cause any damage. As a member of the Lexus forum, I have read a few posts where owners accidentally filled the tank with mid-grade, or regular gasoline, without any major problems, save for some pinging maybe. I agree with everyone else- just add in some octane boost, or simply keep filling the tank with premium fuel every 50 miles or so, until all of the "low octane" fuel has been "diluted" if you will.

When you stated that a friend placed gasoline into a diesel VW, I was most sure that you was going to say the engine was destroyed.... I am suprised that the engine was not instantly destroyed, as it is usually devistating to put gasoline into a diesel automobile. It is not nearly as harmful as accidentally putting diesel into a gasoline automobile.

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2004 Toyota Sequoia Limited 4wd
1991 Lincoln Town Car Executive
1991 Cadillac Sedan DeVille
1988 Mercedes 300SEL
1972 Chevrolet Caprice Kingswood Estate 9-passenger wagon
1973 Pontiac Grand Ville
(Prior MB's: 1974 240D, 1985 380SE, 1984 190D, 1993 400SEL)

Amusing thread to read. Reminds us all of some silly thing we may have done in the past, by accident of course. One time, 100 miles from home, I filled my 500 SEL with mid-grade and and decided to run a gas treatment with it. Did not realize until I had put it in the tank that I had grabbed a same size bottle of "power steering fluid". Refused to drive away until I had spoken to my Mech. at 11:00 pm. Fred at "Fred's Foreign", located in podunk Eunice La. is a great guy. He loves these cars as much as I do. He informed me that they would not have the reputation for longevity that they "earn" if they were so finky as to go AWOL for what I had done. Turns out he was right. Whatever happened must have not been worth noting because I do not remember it. No, it does not have anything to do with my "tranny problems" at the moment.

You will be okay, at least it was "fuel" and not a hydraulic fluid.