This is a rare condition i think not "normal", there is way to many of these tunes. Mine is about two years and other than the dreaded worm clamps, nada, never a code. BUT i have had issue with knock(yes i have tightened up the waste gate) that wont help, but i lke the way it runs withe gate tighter, but with our stinky 91 they sell as ethel is like pawning pond scum and telling me its 12 year old scotch. I tried every after market octain booster ALL are pond scum. Put in a tank of sonoco 100unleaded, oh ya now, that smell oh that smell, scotch, on 91 the car was as detuned as it could get/go. Sunoco/reset the battery to clear it, runs like a crack addict going to the dealer for a fix, now i am at 50% sunoco/ 50% pond scum, still runs good no knock. next fill i should be about 25% sunoco and the hot season is about here with the 120+ degree heat, might need to keep it at 50/50. will see. Boost are from 19-20 in the cool, 20-23hot day, seen 25psi once in high speed pass in 122degree heat of hell.
If its doing some times and not others, sounds like a wire? or a sensor that has a grimlin in it, them damn grimlins are hard to find too.
