i have read that replacing fuel injectors is better than cleaning them? any truth ? do the new injectors need to be adjusted or are they preset already
any thoughts are appreciated. 1987 560 sel with 198,000 miles
Thanks in advance

Try a good cleaner. If problems persist replace them. The old CIS injectors are basic injectors and require no adjustments.

The seals get hard over time - causes air leaks. Replacing them is cheap.

The basic injectors have a spring in them that weakens over time. On a four cylinder engine it's better to replace them as they are "relatively not expensive" . However with the eight the price adds up.

Are you having idling or running problems to cause you to ask this question?

trouble idling, gas mileage, 198,000 miles and i am taking apart throttle body for vaccum issues, current injectors have never cleaned per previous owner.
thanks

Replaced the injectors in my '89 300E at 130,000 miles. Seems like your your car is long overdue for a fuel injector change.

Replaced the injectors in my '89 300E at 130,000 miles. Seems like your car is long overdue for a fuel injector change.

Vacuum issues will cause you the problems you have listed, however if the injectors have not been changed ever from new no harm in changing them. (they are "not that expensive - relatively") I would solve you vacuum issues first though. All rubber pipes and vacuum pipes should be replaced with a car of your age. Change the rubber hoses that feed your idle air actuator.

The first place to start with any Benz this age is
(a) electrical - Distributor,rotor,plugs and leads, grounding.
(b) Vacuum leaks.
(c) Fuel problems - Injection systems