LS180.B Backfiring

[big_green_thumb]

Help! I have a LS180.B that backfires when it's warmed up and past 1/3 throttle. It also 'diesels' when shut down before it's warmed up. It had a kinked fuel line repaired two years ago and was tipped over last year. It's been running pretty rough but has plenty of power, I just can't run it at full throttle. Air filter seems OK. When I change the fuel filter, the problem gets slightly better, but gets bad again quickly. Thanks for any advice.

 

[Tazza]

This is a diesel or petrol engine?

 

[Earthwerks Unlimited]

This is a diesel or petrol engine?

I had an '03 Ls180 and currently an Ls18.5b. Neither have ever backfired. I did some googling and read that Ford Super Duties backfire big-time. From what I read about trucks it is too much raw fuel in the cylinders catching fire, combined with cycling the the glow plugs. Then another google search said in a Cat dozer engine it was the air filter.
The thing that makes me scratch my head is that I thought the LS's have a glowing heater grid in the air intake like my Dodge has. Or maybe just the LS185.b I have now has it.
Do you have glow plugs? If you do, the Ford guys say to not cycle the plugs or that will happen.
If you don't have glow plugs and do have the heater grid, I would think either an injector is leaking, or something is bad on the injector pump.