ORIGINAL: owero01
+1. I only use Exxon or BP 93. Haven't had any ping problems. I also add Lucas or Marvel Mystery oil to the gas for top lubrication.

ORIGINAL: ski

FWIW
Just recently I noticed slight pinging in the 4-6K rpm range at both POT and WOT with 93 octane gas and a 93 octane canned Predator tune. Since pinging had never occurred prior to this, I did some research, and made a list of the possible causes and their cures.
Number 1 is high ambient temperatures. But this was quickly crossed off the list since it was hotter last summer, and the engine did not ping then. Another reason why high temperatures are not the cause is because it also pinged at night when the temperature dipped into the 40's.
Next is a bad load of gas. Immediately before the pinging started, I had filled up at a different station than I normally use. So I ran that gas out without getting into the loud pedal, and filled up at my normal watering hole(Lukoil), which had never caused any pinging. But it did not go away. S..t! I have to stay out of the loud pedal for another 300 miles! Next was Sunoco that's supposed to be quality gas, but which I do not use because it's 10 cents per gallon higher than Lukoil. Still no luck. So a load of bad gas did not look like the cause.
Next is a dirty MAF, which can give the ECU an inaccurate signal, and excessively lean out the A/F ratio. Removed it from the CAI housing, sprayed it with some quick drying electronics cleaner that I had laying around, and reinstalled it. No good. MAF is ok.
Next is a partially blocked fuel filter that can also excessively lean out the A/F ratio. But if the pinging was happening at POT, then that meant the emission control system was in the closed mode, and the O2 sensors were active. In that case, an excessively lean A/F should have thrown a code. But since there was no code, I eliminated the fuel filter as a possible cause.
Next is either a faulty spark plug or a plug wire that's bad enough to cause a rich condition in one of the cylinders, but not bad enough to cause a misfire(which was not happening). At POT this can cause the O2 sensors to send a rich signal to the ECU, and the ECU will then reduce the pulse duration for all of the injectors, leaning out the mixture in the other 7 cylinders, and cause pinging. But once again, this should have thrown a code. Since it did not, a bad plug or plug wire was crossed off.
The last cause my research found was carbon buildup on the piston crowns, heads, and valves. But I did not think that this was possible since the car had only 17K miles on it. However, at a cost of only $7 for a can of Seafoam, I thought "What the heck!" Dumped a can of it into a full tank of gas last week, and after 225 miles the pinging is gone today. That stuff works. Well, it did for me. Plus, the engine idles smoother, revs faster, and has more punch. Where's that 427 AC Cobra that blew my doors in last summer?

NOTE 1: During the time the engine was pinging, I made various adjustments with my Predator to the global timing(retard), to the WOT timing(retard, 2-4K & 4-7K), and to the WOT fuel(rich, 2-4K & 4-7K) in order to eliminate the pinging. I found that the pinging could be stopped only if the global timing and WOT timing were both at their full retard settings, and the WOT fuel was at its full rich setting. But the car ran like s..t at those settings. So I reset everything back to default, and stayed out of the higher rpms(most of the time anyway).

NOTE 2: I may have to continue using the higher priced "quality" gas to possibly prevent this problem from rearing its ugly head again. NAH! I'll continue using Lukoil(cheapest gas around here), and just dump in a can of Seafoam if and when I hear more marbles rattling.

ORIGINAL: F1Fan

Your deposit buildup was caused by using cheap fuel that lacked the additive package needed to keep your valves and combustion chambers clean. Regular use of Top Tier Gasoline brands will avoid the problem all together and eliminatethe need for using products like Seafoam in the future. Look at this link for more information! Top Tier Gasoline

ORIGINAL: sst06vert

THANKS of the GREAT WRITEUP! Good reference.

ORIGINAL: buddha211

Thanks for the writeup. I was having occasional problems with pinging also. Running nothing but Shell gas since I got the car I didn't really think to try a gas additive and was hesitant to do so. I tried the Seafoam and voila, pinging has disappeared. You're not a Seafoam employee are you? Even if you are thanks for the idea especially since it worked for me.

ORIGINAL: ski

You're welcome. Glad to hear that it also worked for you. I do not work for Seafoam, nor do I own any stock in the company(maybe I should buy some?). I'm simply sharing my positive experience with others who may be having the same problem.