My TW dual fuel wagon, 65k on the clock, is developing some roughness and stumbling (what seems like ignition issues) at 60-65kph, just after changing into 4th, esp. if on a slight hill. I'm thinking plugs & leads.

The Q is: how long do plugs last with LPG? BTW it came from the factory with the long-life (ie rear bank) platinums in all 6.

thanks.

I had LPG for a while over 200,000 ks i only have platinum plugs in rear bank those would only get changed every 100,000, standard plugs at the front i would normally change every 30,000ks. I doubt its the platinum plugs or the leads, espesially only after 65k. Does this happen on both lpg & petrol?