Hello all. i have a very imbarrassing story to tell. knowing nothing about cars let alone 4wd drives i recently saw a beat up old fj45 (1978 2f motor) ute and fell in love with it (first mistake). After filling the tank and proudly driving it to work and back every day (10 k round trip) for about a week i decided it was mechanically sound and would take it on the freeway for a 30 km drive at 100km per hour. Ran great to me apart from being very loud and since i was told they were that was that. Went to head home and it would crank but not start. rac and a small fortune for on the spot membership later the guy checks fuel and spark etc says coil and battery not so good and carby needs work then jump starts me and i fire right up. He leaves and i drive home concerned cause its starts miss and splutter a bit now and then. Following day would crank but not start .Next day changed battery, coil and it fired up straight away, great i thought (Another mistake). Off i went thinking all is well to a mates place about 40km away and ute running great to me. Next morning left my mates (started fine big smile worry over) stop at a sevo about a km away for a minute come back out and crank but no start (devastated and hung over). Keep trying and start (yae) drove home another 30km again running great to me. Next day crank but no start (kept trying) then loud backfire and thats where i shut the door and walked away. Sorry for the long winded story , it was for context so you know what a proper job of it ive done here.Here comes the very imbarrassing part. Last resort was to call the guy i bought it from (nice guy) for advice. When i bought up his add on gumtree the answer was glaring at me .Proud owner of an fj45 i think not. To my horror it is in fact a hj45 clearly stated on the add which im told are disel. So on a scale of 1 to 10 just how bad have i messed up and where do i begin. After the laughter dies down any advice would be greatly appreciated.