what would cause my car to surge on lpg and petrol?

[i luv beer]

I have a 1998 EL ford falcon and it surges on both lpg and petrol especially at high speeds when i take my foot off the accelerator and on petrol it revs up and down while ideling i was thinking it was probally blocked injectors or the gas has dried the injectors out and i need new ones am i right?

 

[kelly_f_1999]

dirty fuel system most likey

try a bottle or two of any fuel treatment if its real ba dmight take a couple tanks to clean it