P38 DSE loses power when overtaking

Right, where do i start, done all the searches but none relate to this problem. Only happens every now and again and when it does it wont rev over 2000rpm and there's total power lose,seems like its struggling to pull its own weight. But if you pull over turn it off and wait 10 minutes,there's nothing wrong with it until the next time which could be next week , month you get the idea.
So over the last few months been trying to sort it out, with new parts just to elimanate things,so here is list of parts used so far
-new intake air temp sensor
-new map sensor on fuel fiter head
-cleaned intercooler and new pipes
-new fuel pump,the unit in diesel tank
-new airfilter
-new diesel filter and no air in clear pipes
-cleaned breather on rocker cover
-Faultmate showing no faults with either diesel ems unit or transmission
checked all pipes and hoses for cracks, splits or delamination and everything ok,and turbo works well under normal use so have discounted that.
So i'm open to suggestions,maybe injector 4, but if it is how would i know or maybe i've missed something obvious?

You certainly don't seem to have left much but have you checked the normal gremlins; under-bonnet fusebox, earth leads (don't ask me for any logic here but your fault isn't logical) crank sensor wiring and, as you mentioned injector number 4. To check the injector you need to view it with either an oscilloscope or a 'live' fault reader and that assumes that it's playing up at the time.

If nothing shows up on a fault reading then I've got a nasty feeling that you're either going to have to wait until it doesn't clear or it goes wrong right outside a Rangie repairer.

I'm assuming from the time and money that you've spent already that it's in regular use so you wouldn't have algae, water or other such in the tank.

I'd recheck all the air hoses for de-lamination again, check the intake opening to the air filter, I believe its under the wing liner and check all electrical connections for the becm, engine ecm, throttle pot for being loose or dirty.

Is there any smoke white/black from the exhaust during the fault?

The only other thing I can think of and its very very unlikely is a intermittent partial turbo seizure.

Thanks for replies so far lads, The car is used daily and normally covers 200-300 miles at weekends,so about 450 miles per week. Like i said it happens very rarely but when it does it's always the same symptoms. I've checked and rechecked everything and hoping someone might have had the same experience. I have my own Faultmate,so can read faults whenever but like i said at the moment it doesn't show any faults,I surpose i'll have to wait until it happens again and take some live readings. Car starts fine hot or cold and there's no smoke when fault happens.If you floor it a little black smoke comes out but thats expected to be honest and normally the car is fine,it just every now and again i have this fault,and am abit confused as to whats going on.

A bit of an update, all be it a year after quizzing this. It kept doing it every now and again for a further few months and in July this year i took the powerbox off it after reading some horror stories on there and its never done it since,so i think the cause of this problem was the powerbox all along.

You did miss something obvious in your first post on this. You did not mention a powerbox. That is maybe why you never got the answer to your problem.

wammers said:

You did miss something obvious in your first post on this. You did not mention a powerbox. That is maybe why you never got the answer to your problem.

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Hindsights a great thing isn't it. But since its removal everythings ok, so just letting everyone know incase they have a similar problem

DM68 said:

Hindsights a great thing isn't it. But since its removal everythings ok, so just letting everyone know incase they have a similar problem

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Yep agree but full details are very helpful.