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deMort said:i'm afraid that's an absolute needle in a haystack ..
Fouled plug , old plugs poor injector spray pattern ... a coil faulty , secondary air injection fault .. valve timing .. i could go on to be honest ..
I would sit there looking at the engine values on a tester and probably over several mornings to try and figure out what might be causing it .
not something i can give an answer to
MarkGolf said:Going back to my VR6 days, lumpy when cold was always an air leak after the MAF or secondary air pump.