I have a 92 300E 4matic. I'm getting consistine 13 mpg city/18 mpg Hwy. The manual says 17 city/20 hwy. What could be wrong?

I've check tire pressure and had a tune up.

Thanks
Alan

 

As I can see you have owned Alfa Romeos. If you race the MB like the Alfa's the mpg goes up drastically. But still I guess you need the gasoline lines, pressures, distributor, injection valves and cold start valve checked. This is not included in a normal tune-up. They just sell you new (expensive!!) oil, a set of sparks and a "look" under the hood, filling up your windshield fluid. I personally dont think much of the "tune-ups" since the modern cars dont need this, because everything is electronically controlled. If the electronic goes down you will have severe problems which will not be fixed by a tune-up. (like in your case)
I have two W124 (2.6 liters only) but I never had any mpg under 18 even "flying" on German Autobahns. Both run at about 19.5 to 25 (city vs hwy) and both are well over 185,000 mls and still holding up good. You having the 4 wheel drive could reduce the mpg by 5-10% (my guess).

 

I asked this question in another thread. I only average 19mpg in a 300e. The only response was a 400E owner averaging 22mpg. He indicated the new design 4 valve/cyl helps lower fuels consumption over the 2 valve/cyl. I'm curious what other 300E and 400E owners are seeing.

 

Still makes me wonder why a car with the same size engine less hp and driven civilized would get lower MPG than a car I use to speed and beat on all day long. Granted mine is a 4matic, but 13 MPG city? That like S class consumption. Is it the gear ratio? Emission parts need replacing? or is the 124 model just a gas guzzler? According to the EPA and factory manual its reasonable 17 city/20 hwy. I would love to come close to that.

Alan
92 300E 4matic

 

If you're counting the exact mileage do some experiments. Drive only in the city refill/top it off and check mileage. Do the same for freeway driving. Check and record all variables of engine tuned, oil viscosity and levels good, tire inflaction, wind factor, fuel type, etc. The other variable is driving style. I would expect the highest mileage in the 2.6 for the 6 cyl. motor.

 

My 400E, with the 6 litre conversion gets around 16 city with semi agressive driving and 22 hwy.

 

That is excellent mileage for the performance! I expect that is the result of all the engine parts are precisely balanced and optimally tuned.

 

Wow I would love to have your car. It must drive WONDERFUL! I always said that if my car had 200hp to would be a much nicer car. I can't imagine how great yours must drive.

I really wish I can get that kind gas mileage out of mine.

BTW a friend of mine works for MB as a mechanic and he said he'll have to check my mixture formation, whatever that is.

 

I have a 1986 300E with a manual transmission. I used to get about 24 (average) to 30 MPG (trips to Yosemite). I say "used to get" because when California switched to "California Reforumlated Gas Version 2" in 1999, I haven't seen better than 23 MPG since. Humorously, my 300E now gets about the same mileage as my C43.

As for your 4-Matic in NJ... my parents live in NJ and don't report any gasoline problems. (They have a 1986 300E with 250k miles and get 18 to 22 MPG.) I assume you are running 93 octane. Given that it's winter, have you turned off your air conditioner? (I only ask because I have seen people that run the air conditioner continuously.) A/C, low tire pressure, and poor tire choice could each give you a 1 MPG downgrade. Alignment issues might even give you 2 MPG downgrade--perhaps even more with the 4-matic sillyness. Other than that, perhaps there is something actually wrong with your car.