Misfire at 2500 revs when overtaking?

Hiya.
I have just bought a 2001 Disco TD5 which had been stood for the best part of 8 months. A garage was selling it for a customer who could not pay his bill.
Anyway, I drove the motor for a week, with the diesel that was already in the tank. I have found that the engine misfires at about 2500 revs in one to three gears. Today (Friday) I filled the tank and it is not as bad but still happens occasionally.
My first thought was condensation in the tank causing water in the system. I am hoping that the "problem" will clear once I have run it for a couple of hundred miles. Generally it has loads of power and sounds great, ticks over a treat (no misfires then).
Am I on the right track or do I need to worry?????

I look forward to any ideas.
Cheers all.

yes my bosses car refuses to start when it has less than half a tank of fuel so he keeps a drum spare at all times in case he gets caught short!

change the fuel filter, it's in the off side rear wheel arch.
read up on the fuel 'air' purging procedure - you will need to do this once you change the filter.

check also the wiring loom plug to the main engine ECU, contained in the battery box under the bonnet by the jack. if there's oil in the multiplug, flush it with WD40 and an air line...

Check the turbo wastegate it might be sticking, also I believe that a faulty MAF sensor can cause this coughing

Hiya, Prod's Back and thank you all for your wisdom and guidance. I have to admit I had thought the Turbo may have something to do with it yet hoped it was just condensation.
I am frantically writing the advice down and will get on with the hunt tomorrow (Thursday). You know; the TD5 runs like a dream in all gears, starts first time and holds the road like the proverbial to a blanket but coughs like an old miner (no disrespect to old miners) when it reaches 2500 revs in all but fifth gear. The higher rev band seems to start the asthmatic attack?
Great forum and I am really grateful for your support. Thanks all.
Hope to be back soon, "prodigal-son". Andy.
:5bdriving:

Hiya, I am absolutely gobsmacked at the wealth of info and genuine assistance that is so obvious in the "LandyZone" I haven't seen this kind of comradeship since I was customising vans in the 70's and 80's. GREAT STUFF. Joining your site has been a breath of fresh air and confirms my beliefs that there is heart out there still.
I had planned to tackle my prob's with the mis-firing Disco TD5, this weekend BUT yesterday I had checked my tyres and found the front drivers side to be only 13 lbs pressure, on driving home I realised there was no misfiring!!!!! Well that must have been the problem, I guess???? (tongue firmly in cheek).
If my good luck does not last I shall follow the words of wisdom from the revered "Battenburg" (I love the marzipan around the outside!) and "Sastek", your joint input has been a blessing.
Great site, great folk, greatadvice. Thank you all, Andy
PS: it's nice to be a "junior again".

Amazing! I would never have thought that possible. Certainly not the first place to think of checking.

Brian

still ( as sugested above)worth checking the ECU plug for oil it gets all td5 at some time (a link to U.Ps web site)- www.discovery2.co.uk / Workshop /Injector Harness

Could the misfire actually be the engine over boosting? I have read in the past that the ECU cuts power momentarily when boost pressure gets over a certain level.

Not sure what causes this though! Could someone have been tinkering with the wastegate actuator rod, making it too short and causing overboost?

You say that it is happens in all gears accept 5th. Maybe this is you accelerating, hitting the boost limit in each gear and then settling into a cruise in 5th that is ok boost wise!

Dunno! Just thought I'd mention it

Cheers, Andy

How far has it run in this way? You've only had it a couple of weeks ...

Sounds to me like there was sh1t in the tank, which fecked the fuel filter, which made it run crap on power, and while you've been replacing the 'old' diesel the crap is being cleaned out naturally and it's getting better 'on it's own' ...

You know.... you guys blow me away.
I will check the ECU plug. I have had a few further spits and fa*ts but it IS running a lot better. It does seem that the more use I give it the better it is, PLUS when pulling a trailer it runs like a dream.
I have had it since 24th July 2009 but not "ON THE ROAD" till 30th, that's why i suspected the condensation in the tank. There had been about a quarter of a tank so pulling crap into the injectors from a low tank did not quite fit (sh*tty fuel, yes) and maybe gunked up injectors. The "wastegate actuator rod" is possible but I will have to question the seller about that. I have to say that the Turbo does seem to be making all the right sounds and nothing looks 'freshly' tampered with?
I shall follow the welcomed advice, and check through them, to eliminate your suggested areas of concern.
Thanks again all of you and hope to visit again soon.
Bye for now, Andy (prodigal-son)
PS: Paul D, where abouts in Donny are you? I originate from Askern and the wife from Woodlands. Wasn't sure, as your writing was not showing a Yorkshire accent!!

LOL, originally from Rossington, moved to Nottingham when I was 28 ish to take my degree met a girl and married her and stayed for 15 years or so, then moved back to Kirk Sandall a few years ago.

I went to school in Woodlands, (Born to a catholic family and no schools closer to Rosso) as a child ...