My Stilo JTD (2002) runs like a dream until I've done about 15 miles then the acceleration goes. It will continue to run and will slowly pick up speed then suddenly kick in leaving a cloud of black smoke behind it then not respond again and so on. Any ideas?

Any dashboard displays?

No none at all. A garage checked it but its computer gave nothing but I don't think they had the right software. They changed a sender unit on the accelerator (£330!) but the problem remained. I've used Redex diesel additive but no improvement. A mate thinks the exhaust may be blocking as it warms up.

leehw said:

A mate thinks the exhaust may be blocking as it warms up.

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Would seem to match the symptoms.

Air Flow Meter is a common issue apparently (doesn't create an error) although never had a problem with mine - and looks easy to fit.

Think I'd get a proper report from Examiner (i.e main dealer) before blowing major money.