People tend to forget about hours on a motor too, even at 100k like you think (probably much higher, people lie when selling vehicles always). Hours will wear stuff too... pull the old plugs and take a peek for any oil build up. Cap/rotor/plugs will not last too long due to the high cruise RPM from this motor. Same goes for the fan belt/accys.

I have fairly heavy build up on my M103 on a few cyl, head R&R is planned for this summer. My oil consumption/loss is very high as my head gasket is also seeping up front. I am talking around 1 quart per 500 miles type of use.

Granted the '90+ cars received 'hardened' guides supposedly from MB, I would suspect a worn head easily. Remember also, if the car has not been driven to hot often the cat converter will not light off and can plug up too.



I would hit the main cat body with a mallet and see if you can hear any rattling... along with S-class Guru, a pal of mine had a Turbo Buick where the cat died and the vehicle would barely run past IDLE speeds. Blew out the downpipe donut gasket it was so plugged. Hacked the cat off and all was well.

So, of course do the fuel filter and see where that gets you. If not, then I would pull the cat assy and ream out the precats, they are only there for cold start emissions. You could also ream out the main cat, but the fetch decent cash for scrap so I would just cut it out and sell it.

Do not waste your time putting a turbo on this unless you convert to actual EFI and have the head redone. CIS is crap.

Car will still run without an O2.



Magnaflow/Carsound have universal high flows that are application specific to fit your ride for a good price.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]