Hi, have had an issue with my 98' GU 2.8 over the past few months, every now and then it "misses" like a petrol engine does with fouled plugs, "stutters" a few times and then is right again, has done this 3 times in the last few months, initially thought it may have been fuel, put diesel additive to clean lines/injectors and all was good again only for it to play up again a short time later, I get my fuel from the same place all the time, is this leading to more serious costly problems. Air filter is new, oil changed every 5000. Car drives great 99% of the time, just a little worried atm........

Cheers.