Thread: V8 disco 2 not running properly

Is it an automatic? Does it feel like it's taking off in third gear? Does it rev up ok in neutral?

Hi mate,

How many miles, how long have you had it, ever been overheated, what gas system, ever had 02 sensors done., genuine maf, coils, leads, plugs., when was air filter changed, does it have an engine breather pipe for the lpg going back into the air box?

Just had the same problem after rebuilding the engine (over a 12 month period) Wasn't firing on 1,4,6&7 indicated crook lh coil pack, so have pulled it out to have an auto elec test it before i go any further.....

thanks for the input guys.

It is a manual.

It has been hot and the heads have been done.

Gas is direct injected.

O2 sensors were replaced after gas installed as the gas man had a code reader and this was the only fault that re appeared.

genuine coils, 10mm HT leads, genuine plugs, air filter not changed but blown out, not sure about the engine breather going back into the air box and the MAF sensor that was put in might be that for the 4.6 as the diameter of it was too big to fit into the air intake so I just changed over the sensor itself. Is there a difference with the 4.6 and the 4.0 MAF sensors.

Thanks Ben...

I hate to say this but the diameter of the insulation of the HT leads is totally irrelevant. The most reliable OEM leads I regularly meet in my game are Toyota 5mm leads. It is the construction of the core that counts, not the rubber cover. Many "racing" 10mm leads are waaay too low a resistance and have hardly any damping (inductance) at all.

If you have injected gas and your engine (rocker cover) breather is plumbed to the air box your MAF will fill with oily crud. If you are talking about the 25mm hose that goes via the idle air control (IAC) motor then that MUST draw air from the downstream side of the MAF as this air must be metered for correct fuel delivery.

Sounds like what i've just gone through.

turns out the head gasket had blown (only 10k since rebuild).
no overheating or other symptoms.

get your coolant tested for exhaust gases.

Had the coil pack tested today and all seems fine. They said that they have found in some instances oil can leak into to crank angle sensor and cause this same issue. When I rebuilts the engine i replaced the o'ring on the sensor but not the sensor. looking for that "bang head against brick wall" emoticon