V6 D40 losing power and idling rough

[Petrol Luke]

Yesterday my D40 lost power when taking off from the lights. I pulled over and the idle was jumping from 400 to 900rpm.

I revved the crap out of it and it ran smooth for the remainder of the trip.
My X-Trail did this and resulted in me getting rid of it as it got gradually worse to the point of becoming dangerous.

Nissan say that the D40 petrol shouldn't have this problem like the X-Trail but symptomatically it appears the same.

Anyone got any ideas?

 

[Old.Tony]

If it starts okay, your ignition timing is probably okay, so that leaves spark plugs, airflow sensor, HT leads, injectors and the quality of the coils.

I'd look at them in that order.

1) Replace the spark plugs

2) Clean the airflow sensor with electrical contact cleaner

3) Replace the HT leads

4) Run some injector cleaner through first, giving it a bootful now and again

5) Make sure each plug is getting a nice hot spark and if not, replace the coil.

I doubt it's the air filter, but have a look at that anyway. It won't be a collapsing intake hose, because there's not that much airflow at idle in a petrol (unlike our diesels that suck gobs of air at all times).