Performance issues / backfiring loss of power

[jiisus]

Hi Guys, I have a 98 x sohc 4.0 and after having all my chains replaced and upgraded recently I thought this may cure my problem. The car has a distinct lack of power when I accelerate harder and an audible backfire can be heard when revving though the range, this is happening on both LPG and petrol (sequential system) and wondered if this is electrical or mechanical?

 

[Dopler174]

Have you tuned the truck up?

 

[my98nnj]

Are the cams timed correctly?

 

[mrboyle]

Its hard to tell from your description, but was the problem there before the chain replacement? If so you have a vacuum leak somewhere down stream of the MAF sensor. If it started after the chain work, the timing is likely off on the chain/chains. Either way you have what is called a lean miss and it is not good for the engine.