Mercedes ML270 CDI slow and gutless

[MontyC]

My Mercedes ML270 CDI is very slow and slugish whilst driving and wont rev above 2500rpm and go above 85mph, and struggles with hills , when parked in Neutral it revs up normally so is only happening whilst driving any ideas?

[MontyC]

ManFromDelmonte said:

Sounds like some kind of Limp Home Mode, could be engine or gearbox but I would guess gearbox.

It would be worth doing a bit of googling around this but you might not like what you read.

I have done some googling but it comes up with so many different things. I have cleaned out the EGR valve, given it a full service changed fuel filter I know its not the MAF sensor as it revs fine in neutral I think it is in limp mode but there are no lights up on the dash .

[MontyC]

MX-5 Lazza said:

Sure it isn't a seized brake? Is it better in lower gears?

Hi no checked all the brakes are fine, its an auto wont rev above 2-2500rpm whilst driving although fine if your just sitting in neutral and rev it up, so guessing its not the turbo or waste gate.

[MontyC]

longblackcoat said:

Sounds like EGR to me. You may well have cleaned it out, but the system still thinks there's a problem. My GL did precisely the same; replacement was required, I'm afraid.

Get it on the diagnostic machine and it'll tell you one way or another.

The thing is no dash warning lights have come on so I'm not sure it would even bring up a fault code?. And if it was the egr valve like air mass I wouldn't of thought it would Rev up fine in neutral but may be wrong

[MontyC]

Well after plugging it in I ended up with fault codes
P1187 Rail Preasure monitoring
P1470 Boost Preasure control
P0115 Coolant Temp Sensor

So the main Problem is P1470 but unfortunatly this could be a number of things and involves possibly removing the inlet manifold