Hi, I've been wondering about a weird almost like a pinging noise that my car makes. It has 189,000 kms on the clock, it's a 1991 Camry SV21 automatic sedan, and has been doing this since I bought it, and it doesn't seem to be related to a few things I still need to get done to it according to the mechanics. It's never broken down, has always been reliable, and its biggest issue when i bought it was a need for power steering belts and to fix a leak in the power steering (as well as a number of oil leaks) OK, it makes sometimes quite a loud almost pinging kind of noise when accelerating at slow speeds, and it happens more if driving up a slight incline. (noise is sort of like a much louder version of the engine ping I got from my old 84 corolla when I put normal leaded fuel in it rather than premium - I was also putting lead replacement in that car). However some days it hardly makes this noise, sometimes it makes it heaps. I've been finding that this noise happens less and sometimes not at all when I'm running a tank of premium fuel (like shell vortex) through it, and happens far more then I use ordinary unleaded. It doesn't loose power or anything, just makes an annoying pinging highish pitched metalic clicking kind of sound. Should I be worried, or is this a common problem that doesn't need worrying about? Thanks in advance
