v8 running problems please help

[Tel]

right cars a 3.5 v8 efi (flapper) with a closed loop lpg conversion and megajolt

for the last couple of days no matter what fuel its on it starts and runs like poo missing and coughing with no power atall cant even pull it off the drive if i rev it quite hard it clears itself eventually and runs like normal again and will start again as normal but only after a good 5-10 mins of rough running asif it doesnt like the cold?

any ideas what the problem can be it was running fine i parked it up over night then it started doing it the next morning? 

[Range Rover Blues]

Could be it's not cold starting (fuel enriching) but first thing I'd check is that you get a good fat spark properly timed.

[squaddie_fox]

after that check the valley gasket and the head gasket. easy to change the valley gasket, that was the problem with my old V8, lack of power etc cleared up after a while, but then failed spectacularly on the M6 north bound in a cloud of smoke! :roll: :doh:

[300TDi Disco]

Seems like most 3.5 v8's are suffering at the moment. Mine isn't starting great at the moment but runs fine after a few mins. When i have gave her a run, i find she starts straight away.