My wife's 1997 3.4 only pings with cheap regular. Decent regular or midgrade, no ping. It could be carbon buildup, it could be spark plugs (my 3.4 on the stand had AC Delco spark plugs, single ground, instead of the proper ND plugs <img src="/forums/images/graemlins/shame.gif" alt="" />), it could be low fp, it could be cheap gas. It couldn't hurt to just pick up a fuel pump for your year at the boneyard and swap. Couldn't hurt to put a fuel pressure gauge somewhere, even under the hood, either! Quick way to rule it out. Fresh fuel filter? You might just try to put in some mid or premium fuel in the short run.