Does this happen often? Not really as i have a fleet of these trucks i service. Have ran across three lifts total of hundreds i have worked on. If you suspect a breakage or intake manifold leak, check plugs and if they have white powder look then you can tell which cylinders to look for. Of the 3 i have replaced, i have found them cracked between #1 and #2 and usually the flange will be involved. My opinion it isnt a problem due to fact of huge numbers of the k-series engines i have serviced since their introduction and just 3 in my opinion doesn't call for a concern.

I replaced the main injector, relearned the forklift and it ran great. Sorry I didn't respond sooner guys.

since it was 4 years ago, my bet would be that he followed the advice of "get the dealer to fix it"...
I sure hope it is fixed by now... I doubt the dealer will warranty it now.
;-)

RCAV8TOR, have you been seeing a lot of broken intake manifolds of these motors? [either at low hours like this one, <1000 hours, or the higher hours these motors are getting into now, if so, can you describe where the breakage is happening, (so I will know to look there in the future).
thanx

I wonder if the guy ever looked for a broken intake mani?

I would not touch it, it is still under warranty, let the factory pay for it.
they (almost with out a doubt) need to run the idle air volume learn function, with the laptop. after that, if it still has a problem, valve adjustment and spark plugs, but they should still be under warranty also.
are you SURE your propane is HD5? (not grill gas)