I drive a 1999 E320 that I received from my older sister. I'm hoping to fix it up a bit, she wasn't a car fan and didn't really take good car of the car.

I usually get around 17 MPG, city. Other threads say they generally get 25-29 MPG freeway, so around 21-24 MPG city. I'm not sure what I can do to increase my MPG. I just ordered a Fuel Doctor; I heard it works wonders on older cars. I will keep you updated on that.

Meanwhile, what is my current problem with my gas mileage? I know my sister used 87 octane fuel rather than 91, could that have permanently damaged the car? If so, is there anything I can do to reverse the effects? I use 91 octane only, but I can never seem to get over 18 MPG. Other threads say they have increased the pressure in the tires, but I have kept mine at the 28 psi Mercedes recommends. Should I increase that?

There are also some other things I'd like to fix.
1) My steering wheel shakes when I'm driving at 50 mph+ occasionally. It's always random, and it happens only sometimes. I heard it could be because I need to get my tires rotated? Can anyone verify this?
2) Are there any performance chips that have been confirmed to work with the Mercedes E320? I've been quite interested in them for a while, but I always find reviews saying the major companies are all frauds. Also, would this work with the Fuel Doctor?
3) I want to fix the paint on my car. There are little dings caused by rocks, scratches, and massive swirls EVERYWHERE. I've tried many products by hand, but I have never gotten any results. Do I need to get a Porter Cable in order for these products (SwirlX Remover, Scratch Doctor) to work? What products/car buffers do you recommend?

Thanks for your time, and thank you for helping out a new car enthusiast and MBWorld member!!!!!

 

1) W210's are known to wear their lower control arm bushings and tie rod ends. Start there for the shimmy if you believe tire alignment and balance is good.

2) MB tuning usually entails re-mapping the ECU. Is not a pnp chip.

3) A good detailer or body shop paint person can work wonders with clay/abrasives and polishes to remove paint blemishes. If you don't know what you are doing you can mess it up big.

 

17 city mpg is pretty good ...i get about 12 city and about 24 mpg highway.
But, i drive a 4 matic wagon...so your'e mpg figures are 0k.

 

It's decent, I'm just looking at the other peoples' threads and wondering why mine isn't as high as theirs.