Nissan: engine knock, nissan frontier, frontier 2

Question
I have a 2001 Nissan Frontier 2.4L 4cyl 5 speed standard cab 153000 miles. Since it was new I get an engine ping when the engine is warmed up, I use regular gas, I've tried the next two grades and different brands, same results, it is worse when the a/c is on. I've tried to advance and retard the timing retarding the timing helped some, but it had to go back so far the truck has no power at all.

Answer
You need to go a little deeper. Something may be causing the truck to run lean. Pinging is not always timing, it may be the computer thats doing it. You have a lot of diagnostic work to do and this may need to be looked at by someone who has the equipment to check it out.