Discovery 2 TD5 misfire

Hi all,
2001 D2 TD5 suffering from occasional misfire under load. Typical situation will be going onto full throttle to climb a hill. One misfire then it goes normally. It only happens under load at 2500-3000 rpm.
Having read lots of posts I have:
1. Checked the injector harness. No oil but replaced it anyway.
2. Checked the ECU red plug. Again no oil
3. Checked and oiled the waste gate actuator. It moves freely now.
4. Replaced the waste gate solenoid, and checked for leaks in the vacuum pipes.
5. New fuel filter fitted
6. No sign of diesel in the engine oil

Unfortunately I don't have access to a diagnostic tool to investigate further. Any more ideas before I start spending more money unnecessarily?
Thanks

I had this problem a few years back when I had a TD4. Turned out to be a duff injector.

Unplug the MAF and drive test it so, if it's ok put new VDO sensor

Haystacks said:

I had this problem a few years back when I had a TD4. Turned out to be a duff injector.

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Will a diagnostic identify an injector fault and point out which one? Would be expensive to try and guess.

Update from today: on the way home thoroughly warmed up it misfired several times when accelerating between 2500-3000 rpm then smoothed out and continued to pull beyond 3000.

was that with unplugged MAF? ... though if you just want to ignore me your choice

cmryan said:

Will a diagnostic identify an injector fault and point out which one? Would be expensive to try and guess.

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I don't know to be honest. I would take sierrafery's advice. I was just adding a possibility that it could be a duff injector.

I would go with sierrafery's advice, it helped me get my Disco sorted!! Still grateful Sierrafery!!! ;-)

sierrafery said:

was that with unplugged MAF? ... though if you just want to ignore me your choice

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Sorry didn't mean to ignore your advice, just lacking time to diagnose. The MAF sensor is still plugged in. I'll unplug it on the weekend, and try find someone with a Nanocom

Hi just to provide closure for all the problem was overboost, which was diagnosed when I had it chipped. Once the wastegate screw was wound back a bit the misfire went away. Thanks to all who contributed.