I have started to get a major, and potentially dangerous, problem with my high mileage (150k) 53 reg Zafira 2 litre diesel where, if I have to accerate hard (for instance on a motorway) the engine management warning light comes on and the b***** system puts me into "get home" mode, slowing the car dramatically - which when you are attempting to overtake is disconcerting to say the least.

Googling the problem seemed to indicate that the EGR valve was at issue so we cleaned that with carb cleaner and a toothbrush and took it out for a test drive when theh damn light came back on again ....

So ...A friend and myself attempted to strip down the induction manifold yesterday (failed since we couldn't get the fuel lines off which were jammed solid - how is THAT done?!) but were able to get vast quantities of carb cleaner into the area immediately above the butterfly valves and by using a large bottle brush (the sort that can be used to clean animals drinking bottles) we were able to clean the gunk out .

This time we had access to a OBD reader and so when we had glued the car back together again we took it for a test drive. The engine management light came on AGAIN so we attempted to read the error code....

None. No errors reported. Zilch... The OBD reader (although a cheap chinese one) seems to be working correctly since it read the car's VIN correctly

Anybody go any further ideas?