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Discussion Starter #1 (Edited)
I have a 1988 300ce. I have had the car for a bout 3 months and wasnt sure but the gas mileage is terrible, 10-12mpg. Mostly if not all freeway driving at around 65, is that normal? Going on an onramp that isa little hill by house i have to almost, if not floor it to keep up with traffic. It runs good, no leaks or any other issues driving wise. Trans is a little rough shifting, and sometimes going into reverse. Would that cause the issues? The trans fluid seems like it is dissapearing somewhat, it gets low. Checked when i bought and level was good. Checked about 2 months later and was low but dont see any leaks anywhere.

The other day i noticed the antenna struggling somewhat, going up and down a couple times when i turned off the car. Then it stopped. Went out the next day to start it and the battery was dead. I have removed the fuse so that it doesnt do that, and have had no issues. unfortunately that makes the seat belt light flash constantly and eliminates my dome lights and the lock system. Any ideas why it would start doing that out of the blue? I have had the car for about 3 months and have done no electrical work on it, as everything was fine. I tried searching for this and didnt find anything.

Thank you. Any help would be greatly appreciated.
 

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You might remove the black connector from the antenna motor (in the trunk) and then reinstall the fuse. This should eliminate the antenna from draining your battery until you get the time to troubleshoot the problem. Right now, you have bigger fish to fry with the way the car runs.

Most people in this forum will tell you to establish a baseline for diagnosing the fuel consumption problem; I would agree. This means replacing the normal "tuneup" parts so you can rule them out as possible causes. The list would include:
spark plugs,
wires
cap
rotor
air filter
fuel filter

Trying to diagnose the problem with your car will be more exact once these basics are attended to.
 

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Discussion Starter #3 (Edited)
Excellent I was hoping there was an easy way to disconnect that. I have done plugs, wires seem ok. Cap and rotor and fuel filter are next. Thank you.
 

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My 300E sometimes experiences similar sluggishness but without the excessive gas consumption or rough transmission. When going up inclines, especially in the 20-50mph range the car can seem very sluggish, literally flooring it the entire time :rolleyes:

Luckily there are few instances when this actually happens, I'm still planning on taking it to the stealership to see if they can diagnose the issue, not sure what it could be.. I always use v-power gas, it has new plugs and wires, runs slightly cool, healthy rpm's, good top speed, etc. so let me know if you figure it out!
 

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Discussion Starter #5
Will do. Thanks for the input. I kept seeing stealership and thinking that it was a strange type-o, feeling a lil on the slow side lol.
 

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Guys a couple more obvious ones.

Not long agao I had a mechanic do a zero service on my 300CE.
The service intervals were screwed up on date due to minimal use by PO.

Anyway I too found it to be a bit sluggish but ran well.

The difference after the service where :
1) Engine Oil/Filter (went to a 5W grade instead of a 10W)
2) Transmission Fluid/Filter
3) Fuel Filter

were both changed was dramatic. The car literally leapt off the driveway and kicked down when before I had had to floor it.

So my question is how long ago was this stuff done on your cars ?
 

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Guys a couple more obvious ones.

Not long agao I had a mechanic do a zero service on my 300CE.
The service intervals were screwed up on date due to minimal use by PO.

Anyway I too found it to be a bit sluggish but ran well.

The difference after the service where :
1) Engine Oil/Filter (went to a 5W grade instead of a 10W)
2) Transmission Fluid/Filter
3) Fuel Filter

were both changed was dramatic. The car literally leapt off the driveway and kicked down when before I had had to floor it.

So my question is how long ago was this stuff done on your cars ?
Tranny fluid and oil/filter were done about 6 months/2k miles ago (it's not my daily), I'm not sure about the fuel filter but I'll be sure to put it high up on the to-do list! thank you :thumbsup:

why the switch to 5W versus 10W? are you using synthetic like Mobil 1?
 

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Tranny fluid and oil/filter were done about 6 months/2k miles ago (it's not my daily), I'm not sure about the fuel filter but I'll be sure to put it high up on the to-do list! thank you :thumbsup:

why the switch to 5W versus 10W? are you using synthetic like Mobil 1?
Sorry my biggie I went 10W as opposed to 20W. and yes it's synthetic !
There was no particular reason other than I wanted to use a Mercedes Benz Approved Oil as I had no idea what was in it before.
As I understand engine oil, as a general rule of thumb an ageing engine would probably appreciate a slightly lesser viscosity oil on startup than something thicker. I believe all engine oils work as lubrication at EXACTLY the same temperature (or thereabouts) when warmed up.
However at STARTUP, which is where the poor old engine first starts moving its gizzards around, oil at its resting temperature varies greatly in its viscosity and thus higher grades of oil such as 20W and 30W are quite thick and "gluggy - technical terminology hahahah). So when you first fire up your beast with these "gluggy oils" the engine works harder until such time as the operating temperature starts to thin the oil out to do its work at its normal temperature.
By choosing a lower viscosity oil I believe I am putting less stress at startup on an "ageing engine" and hopefully prolonging the life of said engine.

I chose the following:
LIQUI MOLY
SUPER LEICHTLAUF | 10W-40
SPECIFICATIONS: API SL/CF, ACEA A3-04 / B3-04
APPROVALS: MB-Approval 229.1,

It was also a bit less expensive than some of the other recommended oils that were available here in Australia

Cheers
 

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Fresh engine oil and a transmission service isn't going to solve the problem of your initial post. Follow the suggestion of Donf and read the link he posted. In most cases, a minor tweaking of the Air/Fuel ratio solves the sluggish behavior and poor gas mileage.

You can also use the seach function of this forum and read all manner of post on this subject. In proper tune, you should be getting upper teens to low 20 mpg in town and mid to upper 20's on the highway.

Good Luck,

Jayare
 
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