alterastro 
I've looked further into these codes (P1392/93). I suspect my last post was a scarlet kipper. Jag and Ford and poss others indicate that it is something to do with the ECM/VVT and the glow plugs or Gap (which doesn't make sense when talking about the VX). Have you tried clearing the codes with the SG2 and then do the codes return?
Kirk
PS I also found this on the web.....
"I have a 1997 isuzu trooper automatic .6 cyl. and i have been trying to get it inspected for months now and it comes up with the code p1392 "random misfire"the first mechanic told me to go change my spark plugs so i did then i took it to someone elts they said change fuil fillter i did,then still didt clear it up so the said coil packs so i changes 3 of them that looked a little rugged then they said change my mapping sensor so i did that aswell..i called isuzu dealer
3 hours away said they couldt help me .no one can figure out what it meens it comes up as a g senser but mine not being a deisel so it doest have a glow plug or a gsencer they said..so im lost ..please help this woman is seariouse distress.."
Answer
"Hello,You may have an o2 sensor that is causing a problem.The sensors function is to read exhaust gases before convertor so the computer can run injection system rich or lean.If it runs a little rich it can misfire one or more plugs and wont pass emissions test.Thanks for your question.Roger"
