I have been experiencing problems on my 1989 300E with the cruse control..it locks out after a few minutes and then its difficult to engage again. The car may only travel 1.5 KM and then cruse switches off. I have visually checked the control unit below the inlet manifold...everything appears in order...any easy suggestions..Thanks

A quick try is make sure your tires are all good and the same size. The wheel speed sensors on my car picked up the difference between tires sizes and shut off the CC. Also do a search on throttle actuator - the two are related.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles