Hello,
Sad to say but this is just what happens as cars age. Causes include a need for alignment and tires that may be of various ages use levels (i.e. front vs back). The best ways to fight the rough running is to have regular tune-ups. I have a 1997, and it will run rough at times, but after tune-ups, seems to be a much happier little automobile. =)
Best of luck!
CarGrrl
So at high revs or at high engine load it is running rough? Hand full of problems can cause this...
When did you last replace spark plugs and or wires? Thats the most likely culprit.
Possibly could be a leaky valve cover gasket which can cause ignition problems.
A valves may need to be adjusted or may be sticking
Timing problems, ignition or valve timing problems
Having not seen the car or being familiar with it, that is my amateur opinion. If it isn't burning oil that is.
MAS air flow meter at it's end, it should be throwing a code about now that says “fuel trim”. Get a new mas air flow sensor insert around $250 at www.germanstar.com you should be good as new. You'd be surprized just how much power you lost with the bad sensor. On the later cars it affects the auto trans shifts too.
Try cleaning the MAF before blowing the 250 on the new sensor. i I had the samething happen to my 95 c280. On the M104 engine things run alittle differently than what is a classic engine for one thing there is no One ignition coil. another is that there is not rotor or distributor. It was one of the first modern engines that we are used to today. Check and verify that each of the coil packs are in good order any with white stuff on the side means its a coil that WILL burn out I lost 2 cylinders after 6 months of that acting up while in a college road trip from NY to FL . I freaked out . The car limped from VA to NY home and I checked the coil it smelled burned and it turns out that it was the original coil from 95 while the other two had been replaced . Check yours and let me know what you see ie. part number and any residues. oh and the throttle plate typically gets dirty from oil so you may definitely want to clean that with some STP throttle body cleaner.
