I have been filling up my 99 Blister fender 3.5 DOHC with LRP since I got it - and that is what Mitsubishi agents / previous owner recommend me. On other threads on the net, the advice is to use LRP because of a performance increase. I haven't had any engine problems due to the usage of LRP for the past 15 000 km.
Theuns can you please advise why you stated to fill up with unleaded?
look underneath for a catalytic converter. If it has one then you MUST use unleaded. If it has an oxygen sensor in the exhaust downpipe you MUST use unleaded.
Other than that there is much debate what is good or bad or better.
There are other reasons not to use LRP too. For instance, the original spark plugs for the 3.5 DOHC V6 are of the expensive platinum tipped type that should last for 90000 or 100000 km, if you run unleaded. If not, the plugs are fouled much earlier. Of course, you could opt to run LRP and replace the plugs much more frequently, but that is a bit of a mission with the Mitsu V6, especially the DOHC with variable intake manifold. Perhaps this is the reasoning behind the NAAMSA recommendation?
Gerrit Loubser
2003 Toyota Land Cruiser 100 VX TD
2003 Mitsubishi Pajero 3.2 DiD LWB A/T Gone & missed