Ticking or pinging??

I have a 2000 Rodeo Isuzu 4wd. with less than 50, 000 miles on it. It has been pinging lately. I have tried Marvel's mystery oil gas additive along with some other..STP I believe. It goes away for awhile and then comes back. I have kept my oil changed as dealer recommended. Recently I have also stopped using 87 gas...went to 89 and am now trying 93. The 93 seems to give the engine more get up and go and has stopped some of the pinging but not totally. I am worried about running 93 in it. One it is expensive and two it is not recommended for this vehicle. I don't know if I would call it ticking or pinging. I think it is a ping. It happens on take off most of the time. Any suggestions? Thanks, VJW P.S. It kind of sounds like a lot of rattling.

have you checked your oil level? i have a 94 rodeo and usually need to add a quart every two weeks. my brother has a 95 and has to do the same thing. neither of our cars leak or burn oil so where the oil goes is a mystery to me.

you're using 93 octane and still getting a ping? do you have a ridiculously high compression ratio? since there aren't many aftermarket performance parts available for our rigs, i can't imagine it could be very high unless, for whatever reason, you shaved the deck.

my guess would be just valve noise. not to worry you but if you've been keeping up on the regular 3000 mile oil changes, you may have a problem with your valve train.

I'm no expert by any means, I'm just letting you know what I think.

I don't know what the compression ratio is. I don't know what shaved the deck means either. Sorry, I think for a female who is a nurse, not a mechanic I do know a little about engines but the terminology here is lost on me. Thanks for your suggestions though. What would I have to do if it is a valve train problem? Have the valves adjusted? Is that expensive? If it is just valve noise do you have any recommendations as to how I can get them to be quiet? Is there something I can add to the engine such as slick 50 to quiet them or would I be wasting money? Again, thanks, I sincerely appreciate your input ....any ideas are worth considering. VJW