Pinging at Low RPM

[fastjaw24]

Long story short. I purchased a 2006 RC Ram SRT-10 with 87,000 miles about a month ago. Been going over it every chance I get and trying to get it in tip top shape and fixing everything I can find wrong with it. Car is unmodified(as far as I know) except for a Magnaflow catback exhaust(May be blown out like they tend to do plus its been on there for a long time). The tank is full of 91 octane fuel which is about the highest we have here except for BP which has 93 but have to go across town to get it.

I just noticed the other night when driving slowing in 3rd gear I slowed down for a round about and did not down shift and the car got down to almost idle rpm. Then accelerated about half throttle after leaving the round about and noticed heavy pinging till at least almost 2500 rpm's. It sounded like it was starting to taper off getting close to 2500 rpm's but the exhaust starts getting fairly loud by that rpm so its hard to tell exactly how high the rpm's go till it stops pinging completely.

Now the pinging sounds like a can of marbles shaking or a can of bb's also. So I assume that is detonation I am hearing. I went ahead and tried it 2nd, 3rd and 4th gear at light,medium and full throttle and all of them pinged from around 1000 rpm's to 2500 rpm's with all test I conducted. My question is this. I know more load and heavier vehicles and definitely run the risk of pinging easier then a vehicle that is lighter or not being lugged as bad. Obviously I do not want to purposely make it ping over and over in case it may potentially cause damage. So I'll try to keep the rpm's up until I get this problem solved.

1. Is this pinging normal for a Gen 3 motor at lower rpms?

2. Is it possible to check if my truck has a tune on it somehow?

3. Maybe run this test with 93 octane fuel from BP or use some octane booster instead?

4. Could a tune fix this or be worth fixing?

5. Anyone have any experience with a J&S knock sensor system? Heard nothing but amazing things about these and how they have literally saved 1000's of motors and it can do a whole lot more than the stock knock sensor. And are pretty reasonably priced. If it saves your motor once it has paid for itself 10 times over.

Any additional recommendations or advice would be helpful too. Trying to learn all I can about these trucks and motors. Thanks in advance.

Edit: When are O2 sensors recommended to be replaced on these motors?