2008 4.4 v8
 

Hi, Since it's got colder, two mornings in a row when i start the car it's really lumpy, like it's not firing on all cylinders, then after 2 or 3 minutes it's OK, the second morning it took a little longer. Has anyone experienced this. Ian
Should mention it's dual fuel Petrol / LPG. although it starts on Petrol.

It maybe have something to do with fuel pressure.

I recently had a high pressure fuel pump fault with my 4.4 v8 LPG Prins.
It ran rough with starts then would sometimes die after a few sec. other times not.

if this could be of use , i'll provide more info.

It has been mentioned about a fuel return line. (im still investigating this)

I'll refer u to link.

On diesels when this happens, often a new fuel filter cures it.(Normally an 'engine warning light' comes up on the D5S engine) Worth a try if filter not changed for a while?

Sounds like a good time to invest in VIDA/DICE. This diagnostic tool would allow you not only to check for potential sensor issues but also to measure fuel pressure in real time.

Also, do you know when the spark plugs were last changed? If they've been missed by the previous owners for some time (i.e. 'essential' rather than scheduled services being carried out) they might be in poor condition and hence giving poor performance when cold.

Hi, It was ok yesterday morning, but this morning it was lumpy for about a minute then OK, this time the engine light has stayed on.

i am just charging my vida/dice computer and will give it a go tomorrow. last time i used it on my D5 it wouldn't recognise the USB.

@ian ferguson, did you manage to solve the lumpiness problem?

No. i didn't find the problem, but it just stopped doing it, and the engine light went out