V8 ENGINE ANY IDEAS?

[steveieb]

Following the wait to join the Towcester run last weekend the following happened:
1/ whilst queueing up to move off there was the equivalent of a small "pop"  explosion/back-fire in the engine
2/ then driving 8 miles in two hours the car apeared to be struggling to gain power and "jerking" at higher speeds on the way home ie @ 50 plus.
3/ on using it today it started ok but sounds "rough" and is losing power and still jerking at various speeds!
any ideas...........................
sounds expensive!!!
(hope not)

[MuddyMike]

Depends on which V8 you have, if flapper valve EFI then it could be the flapper valve damaged by small backfire through thhe induction system.

Mike

[Range Rover Blues]

Is it on LPG? It's uncommon for a V8 to backfire on petrol but quite common on gas.

Anyway, it's probably dislodged an air pie giving you a crap reading on the MAF sensor, or as suggested it's bent the flapp if you have the flapper EFi.  Check everything thoroughly for splits, leaks, hoses adrift etc, could well be a small air leak.

I've had a missfire b***er up my servo, blow my airbox apart, reduce the flexi inlet hose to tatters but then on gas you have a volume of explosive mixture in the plenum that you don't have on petrol.