Help!!!!!

Ive had loads of problems with my car lately. Cut a long story short the powertrain malfunction light keeps coming up on the dash (red light with exclamation mark inside a cog). Keeps going into limp mode.

So far i have had the egr valve changed as kept sticking once cleaned. Light vanished for a week then reappeared. Took it back to the garage and they found some carbon in the pipe and cleaned it out. Problem solved...... well so we thought!

I have driven about 60 miles and now the light has come back on yet again. The weird thing is when it comes on and causes the car to limp i pull over turn the engine off and on again and the light diappears and car runs normal again!!!

The garage who fixed the egr valve are really good but far away from my house and having to take it there is a real pain.

The code that is showing now is p0087. The car judders sometimes whilst idle, never when excellerating only when waiting at lights etc. There is no smoke, no stall, drives fine otherwise.....could it possibly be just a sensor or something simple? The egr code keeps coming up too? Garage have checked the egr and its not faulty?

Any help would be very appreciated! Its a 2008 1.6tdci -no dpf fitted and has done 117k miles.

Im seriously loosing the will as i must have took it to 5 garages and each time they put on diagnostics and its costing me a fortune.

Thanks

Michelle