Hello, first i introduce you to my car:
1997 year Mitsubishi Galant 2.0 (4g63) GLS, mechanical transmission.

Well, i'm happy with my new purchase except it's hunger... Fuel consumption in city is about 17l/100km, highway - ~12-13l/100km. It's really too much!

What i've did:
changed engine oil, oil filter, air filter.
Did engine diagnostics, here's the results:
http://img411.imageshack.us/my.php?image=resultsih8.jpg
http://img503.imageshack.us/my.php?i...esults2vi4.jpg

as you can see - everything's ok (errors were deleted) except 2nd lambda probe, but i believe its function is only diagnostic, so here i don't see any problems.

Also a few facts:
Sometimes, when engine is idle, rev drops to ~600rpm and you can feel strong vibration because of it. After 3-6 seconds it's back to normal - ~750rpm.

When driving downhill, using 3rd, 4th or 5th drive at 60-90km/h speed, car slows down and i sometimes event have to push accelerator. Strange. With Renault Laguna '95 i always had to use brakes.
I've passed MOT - said thant no problems with brakes or wheels..

Can you suggest anything? What to look for and try?

Thanks for your answers!