-check for leaking pre combustion chambers. Both my cars had leaking ones when i bought them at around 165,000 miles.
-Streched timeing chains.
-cruise control problems.
-Make sure turbo is producing boost. alot of the time on these cars the vacume solenoid valves/transducers leak and fail and the car won't make boost. Easy check is to check zero to 60 times a properly working car will be around 13 seconds if i recall.

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2005 e320 cdi (132,000)
2005 Jeep CRD diesel--2.8L (138,000 miles) wrecked, insurance took
1993 Mercedes benz 300D 2.5 Turbo Frybrid powered. (336,000 miles) wrecked and sold as parts car
1990 Mercedes benz 300D 2.5 Turbo (170,000 miles) wrecked and sold as parts car

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