Scorbs

Had recent diagnosis check but showed nothing. I think the air bubbles maybe normal. As for the trips about half short and long, and often do a long run at speed on motorway. 160k miles, it's seems to me to be electrical maybe a sensor to do with fuel supply. One thing I don't understand is why there is no response from the throttle.

Hi Everyone I have a mk2 c5 2.0hdi 138hp registered July 2006. This car has a rather irritating problem which I can best describe as fuel starvation, which is very intermittent.. This is what I'm experiencing, the car starts and runs without problems loads of power no back smoke out the back. But after a bit (can't be more precise as the problem is intermittent) the engine will run as if it has no fuel (sort of misfiring once it has reached tick over speed. When this happens the is no throttle response at all, also I have noticed that there seems to be air in the diesel primer bulb (not sure if this means anything, except if you squeeze the bulb the engine will pick up and run). When this happens I can switch the car off, start it again and all is OK. I don't think this is the lumpy running problem, which can be fixed by blanking the EGR valve. I don't get any problems during driving at anything above 1000 rpm, and if I keep the revs above this it runs fine. To add to the fun once the car has thoroughly warmed after a long drive the problem goes away. So I'm hoping that someone reading this forum has come across this problem and found a fix. I am assuming it is some sort of electrical problem or fuel pressure issue. One other thing, is I do get air bubbles in the fuel line between the fuel filter and fuel pump, I have read this maybe normal although it doesn't seem right to me. Finally, this isn't the first citroen I've had. Have 2vc's, Dyane's, BX, Xantia, XM, 2cv Van. So I'm expecting it to be some strange citroen style querk. All suggestion welcome.