2008 model rpm problem

[edwar64896]

Every now and again my 2008 tucson simply refuses to rev beyond 2800 rpm. Doesnt matter what gear I am, its as if a rev limiter has activated. Really annoying when on the motorway, or trying to go up a hill and I need to change down. Gut tells me a sensor is sketchy or something up with the diesel turbo.

Any better ideas?

[PhilHornby]

I've experienced a couple of similar faults over the years on several different vehicles - absolute sods to fix

Are there any (even if seemingly unrelated) clues?
Noises, warning lights, smoke etc?

(I had a Freelander whose clutch pedal switch came off the pedal and dangled freely (unnoticed!). The Hill Descent warning light came on, but the car was OK for months - until the switch started making contact with things - which triggered a 3000rpm rev limiter. Same car had the pre-cat come loose in the exhaust manifold, that occasionally blocked the exhaust. Both faults manifested themselves at the same time!)

Does the car rev freely when stationary? - is there truly a Rev limiter at play, or is it just seriously lacking power?
Are the brakes binding?
Are the accelerator pedal and cable intact and operating fully?
Is the electrical system functioning normally?
(I was going to suggest a compression test - but thinking about it, I have no idea how you do that on a diesel ; )

If you (electrically) disconnect each fuel injector in turn, do they all make things worse? (Is each cylinder doing something useful)

I once had a turbo fail on diesel Mondeo - it was seriously down on power, but I don't remember a Rev Limiter style limp mode. It was fairly new, so I didn't get involved in repairing it.

A scan for Fault Codes (using a factory tool) might be worth paying for.

(This reply may be food for thought, if nothing else...)