Ford Galaxy engine judder, engine fault light, limp home mode,

After a spell of steady low speed driving 40-60mph, on acceleration the engine misfires and enters limp mode. Engine runs perfectly on tick-over but will not rev up much. Switch off for a minute or two and restart and engine might run OK or fault might happen again. Suspected fuel system and put Redex fuel system cleaner in tank. Went much better on test run and have only had occasional hiccups but no fault light. I have a suspicion the fault might be the EGR valve sticking as the throttle is opened. Has anyone any experience of the exhaust gas recirculate valve?