V8 3.9 1990- backfiring thru intake and won't start!

[Tubs]

Hello, I was wondering if any one can help. I have a v8 range rover classic 1990 reg which I off road. Long story short ended up in deep water. Filled the block up, so pulled the plugs and turned it over to pump the water out and managed to get it started. Then drove 30 miles home with every thing working. Changed oil and water new diss cap and leads,plugs. Drove ok for a couple of months then I started to get problems with stalling and lose of power. Now all I can do is start it but it will not idle so have to keep revs up and it backfires thru the intake and cuts out when you let the pedal off. Do I have a problem with a valve or a push rod? Any idea's? Many thanks Tubs 

[squaddie_fox]

Have you drained out the old fuel and pushed through some new stuff? If you were in deep water then the petrol tank will have got water into it.

[SI COOPER]

is it on gas i had the same problem with mine backfiring through the inlet but it was down to the gas set up