[2eyefishclaw]

the noise you are describing is most likely what is called spark knock caused by predetonation (timing issue) do not use higher octane fule for this will probarbly only agrivate the situation. There is a PCM calibration update avaiilable for your Rodeo (DEALER) which may help. NO it will not be cosidered as a warranty issue because it is treated as an adjustment which is covered for only 12 months or 12000 miles good luck I hope this info helps.

 

[2eyefishclaw]

there is no service bulliten for the spark knock and if you have a decent dealer they wont charge more than $30/$40 Isuzu used to pay up to one hr. for this but if the dealer is equipped properly, which they should be it will not take more than ten minutes for an update programming