simon64
New Member
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hi my 93 RRC 3.9 v8 has developed a backfire it does it on lpg or petrol but only if i go over 4000rpm any ideas regards simon 
backfire
- Thread starter simon64
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G-man
BBQ king
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i think its caused by a vacuum leak check your vac hoses! also check and clean your plugs
gavbriggs
Well-Known Member
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- Sheffield uk
get new plugs and leads! check air intake is sealed and connected properly. is the backfire down the exhaust or up the air plenum?
simon64
New Member
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hi i have just had new plugs and ht leads fitted the back fire seems to be mostly down exhaust but have had it go bang under bonnet too
G-man
BBQ king
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- essex.... in the middle somewhere
has the timing been checked? i still think you should check for vac leaks
simon64
New Member
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the guy next door a 70 yr old retired mechanic checked timing using a timing gun he said it was ok but dont no how good he is i sadly no nothing when it comes to this sort of thing please forgive my ignorance what do u mean check 4 vac leeks
