intermittent missfire

Had my 52 plate discovery with 107000miles coming up to 3 months without any problems other than felt a bit stifled, until Monday. Topped up with fuel to fill tank, traveled roughly 30 miles at a constant 60mph climbing a bank on motorway and suddenly started misfiring yet still pulling. Left the motorway and headed for Land Rover dealers (arrghh Stratstone) as I was desperate as I had my three year old grandson in the car as we were going on holiday. I left the car switched off whilst I built up the courage to go into reception! came back out and started the car to try and limp home in it and found that it started without a problem no missfire, driving perfectly all the way back home I changed cars and went on holiday. Upon my return yesterday I checked everything was alright started the car and let it run on the drive for half an hour, still no problems so took it for a test drive on a fast road topping 70-80mph threw it round a couple of roundabouts and returning home it started missing the same. pulled off the road, same procedure turned engine off only this time restarted engine straight away and drove home without a problem, no misfire, perfect. sorry for this looking like my last will and testament only I am new to forums and don't know how to abbreviate. I do apologize for not introducing myself. Hi I am Kcburty could somebody help? Things I have done to improve the car

1) De -cat downpipe
2) EGR blanking kit
3) Straight through centre pipe
4) K & N air filter

sounds like your overboosting and ecu is cutting power

Hi Jonlad, Is it a result of what I,ve done if so how can I rectify the problem if not whats the cure.

you would need to have fault codes read by a diagnostic reader, that will give a code relating to the problem, then work from that

after reading some of the other peoples problems and this old niggle in the back of my head, so I pulled the ecu out and yes lots of oil in the red plug cleaned both ends and checked waste gate was operating and seems ok but I will do as you advise but also change the loom and let you know many thanks.

Hi there Johnlad, well your probably laughing up your sleeve but its back went out today 15mins into journey and fart fart stopped fired her up again and away, thing is there's no warning lights coming on, now the cost around my area to get the codes read is crazy, so I'm going to buy my own which is the best for me Hawkeye or Nanocom I don't want to buy something that I cant use.

If you tell us where you are somebody maybe near enough with a diagnostics reader to help you out! Defo sounds like an overboost though if it goes away when you recycle the ignition. You will not get any warning lights for an overboost error but the ECU will switch to limp mode. However that does not fit with a misfire which is normally oil in the ECU loom and plugs and sometimes in the ECU itself.

Hi Shifty 1962, I'm near Cardiff CF15 9NQ. I may be wrong when I say miss fire it could be limp mode only as I've not experienced limp mode before, I assumed it to be miss firing as it sounds like a miss beat and lack of power if that is limp mode then I'm mighty relieved. Do you think someone is close to me with a decoder I'd be most grateful. I took it all apart yesterday and there were traces of oil in the red plug so I cleaned it all out and also cleaned the injector end plug I checked it today and it was all still clean, I will replace the injector loom as a precaution.

Limp mode will not result in a missfire but merely reduced power as the ECU cuts back on fuelling.

Some other things you may want to try are diconnecting the MAF sensor on the air box pipe and seeing if the engine runs better. If so your MAF is kaput.

Or you could try removing and cleaning the MAP sensor on the inlet manifold as this measures the boost pressure.
Just soak the tip in oven cleaner for five minutes or so then flush with paraffin or white spirit.

Cheers Shifty. I'll try those suggestions thanks I changed the boost solenoid today for one I had kicking around off an auto though no difference 10 miles and limp home, the actuator is free and operates with resistance as I assume it should. I took the plug off the injector harness at the head full of oil again so I will replace that tomorrow, will a maf off an auto be different to a manuel as I have a brand new one somewhere incase thats us, any luck on someone close to me with a code reader.

I'd try turning the turbo down a bit. Make the actuator rod longer by about 5 turns and see what happens. It will mean the wastegate opens earlier which will stop the turbo overboosting if indeed that is the problem. You want a maximum of 1bar boost pressure at the inlet manifold for a standard TD5. If you have a boost gauge it will help but it will only read properly when the engine is under load.

Well boys, that old niggle of mine paid off so before I went selling my gold fillings to fund a diagnostic check with my local Land Rover Independent guys. I took the plunge and purchased a new injector harness from Bearmach, its an upgraded one also a new rocker gasket. Spent a few hours fitting it and cleaning things and started it up straight away it sounded different, smelt different and the drive well it was like a new car. I've been everywhere up long winding hills motorways and it hasn't missed a beat, £61.00 well spent. So thanks for all the suggestion and help.