I have the same ones on my 87, 260E, >350K miles, I have changed the seals and used compressed air along with fuel injector cleaner spray to just clean them. Most of them make the same type of spray and sound, one or two had a different pattern and sound, but still sprayed o.k. If you put new ones, ofcourse they would perform better BUT given the condition of all other parts in the fuel injection system of my 20 year old car, they will not largely determine the overall performance. I would expect only a marginal improvement in the overall performance.

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Saumil S. Patel