Engine Ping
 

My 1991 has developed a ping as in detonation I believe it is called. Here's the lowdown. She's a 1991 with 54,000 miles. It has the 22RE engine, two wheel drive. I replaced the timing chain, sprockets and chain guide at 49K. I also replaced the air flow module I believe it's called, the device on top of the air filter box. Has run flawlessly up until now. Timing is spot on at 5 degrees using the jumper which is to be used when timing. Slight revving takes it to 12 degrees. But now, under load it pings. I thought that perhaps it could be attributed to bad fuel but after two tank fulls it remains. It is especially more pronounced when I've sat and idled for awhile and the temp gauge goes up to mid-range which is the highest it's ever risen. In the small amount of investigation thus far I believe I've read that it could be a wonky distributor or one or more of the sensors sending info to the ECM or, the ECM itself.
Are there some issues that tend to surface with the this engine that this can often be attributed too? Thanks for any input.

Did you replace the tensioner when you redid the front side?

The ECU should be retarding timing when it detects engine pre ignitions, are you seeing this on the timing light?

​​​​are you using lowgrade fuel, the octane level is dictated in the owners manual I don't recall the number maybe 87-89 (I know I can't run either of the two lower grades, there are four here in nebrasky)

Yes I replaced the tensioner. I'm using 89 octane fuel. Not sure how to go about your second question.

It could possibly be a bad EGR Valve.