E220 cdi with loss of power

[Lorro]

Hi guys, I have an E220 cdi that occasionally looses power. Basically what happens is I could be driving all day no problem and then pull up to a set of lights, go to pull away and I've got no power and can only get to about 20mph, then suddenly all power is back and I'm away. Also now and then it goes from idling lovely and smooth to very rough and then back again. Any ideas ? My mechanic got a fault that said "low fuel pressure" but he's unsure where to look for the problem. Would it be fuel pressure sensor ? Air mass metre ? Any help where to look would be grateful

 

[Terry_]

Its best to get it checked properly on star/ Although your problem could be as simple as a fuel filter!

 

[Lorro]

I'll get the mechanic to change the fuel filter and at least eliminate that as a cause of the problem, cheers