Mondeo losing power under acceleration

My 2012 Ford Mondeo (39,000 miles) 140 TDCI is losing power under medium to hard acceleration. When accelerating from 1900rpm onwards the car intermittently dips 100 or so revs, at around 2100-2300rpm, the car then usually accelerates through as normal. This only happens in 4th, 5th or 6th gear, and usually when accelerating firmly, like when entering a motorway.

The car is under warranty and went to the main dealer with the fault. The first time they diagnosed a fuel filter and fitted a new one. This made no difference and they diagnosed a fuel metering valve and changed this under warranty. This made no difference. The third time they said it was the clutch, which isn’t covered under warranty.

I asked them to guarantee that if they changed the clutch at my expense and the fault wasn't fixed that they would refund the cost of the clutch. However, they’ve refused to do this. What should I do?

Asked on 1 December 2014 by ford power

Answered by Honest John
2000-2300rpm is the point of the rev range when the engine should be developing maximum torque. If you accelerate going uphill in 4th gear and the engine revs rise faster than the car is going, then the clutch is slipping.

But what they might mean by 'clutch' is dual mass flywheel that is designed to absorb excess torque, but may have lost some of its springs in your car and may therefore be over-reacting. If it is the DMF then that is a warranty part, not a wearing part like a clutch. The other possibility, of course, is the turbo. If the oil feed pipe to the turbo bearing is partially blocked with carbon that will prevent the bearing from lubricating properly.
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