mileage drop
 

During a cold start, I had to crank my '86 300E (69,000 mi) a little longer to get it to start. When the engine was warm, there were no starting problems.

So as a first step, I used a bottle of Techron Fuel Injector Cleaner. Since that, my mileage has dropped from 21 mpg to 18 mpg.

(With the techron treatment, there was a slight improvement in the cold starting.)

Any suggestions to bring it back up is greatly appreciated.

Thanks in advance.

cheran