Well I was wondering why my truck knocks an pings under load especially at like 45 when the od kicks in. When I run 89 or better it stops somewhat. I was jus wondering what everybody run in there truck, an if there is a fix for that. I dont mind the extra 10 cents a gallon. I want to know if there is something wrong. The truck is stock. 3.55 gears 265 tires, plenum was done 5000 miles ago. That showed know improvement with milage or ping.

 

What spark plugs do you use?

I run 87 or 89. Never had a problem with pinging or anything at any speed with my 5.9.

 

i gotta 5.9 gas and i have to run shell 89 or mine does the same thing if u use these mom and pop gas stations its horrible might wanna put some octane booster in with it to see if it helps it it sure does mine...

 

Same thing as you Dontdodgeitramit. Knocking decreases significantly with 89, and I would say theres a 99.9% knocking reduction with 91. No signs of plenum leak for me last time I checked.

 

Try running quality gas. I like BP gas. Anyway do you have the Autolites? If so take those out and put some Champion plugs in and see if it cures it.

 

Really? I've got autolites in mine, might try those eventually.

 

I didn't really like the Autolites when I ran them and lots of other guys have had the same experience. They don't seem to last long at all in Dodges. A buddy that used to work at the dealer told me the same thing that unless I wanted to replace them every few months to just go with the Champions. He said the Autolites just didn't seem to last in the Dodges. However in Fords they do great since thats what is recommended for them.

I like the Champion plugs much better in the Dodges.

 

I'll have to check them out.

 

The Champions are what come stock in these trucks and imo the best option.

 

From your avatar, it looks as though you've tried Seafoam before. I would do it again. With stock timing,predetonation at low rpm/high loadis usually caused by carbon deposits in the combustion chamber.The deposits effectively raise you cylinder pressure and they also retain alot of heat. Even though your plenum gasket may be in good shape, a lot of oil vapor and blow by crap gets sucked in there via the pcv valve during harddecceleration. A good way to do a Seafoam treatment is to remove the plugs and pour a ****load into eachcylinder. Let it soak for about 3 hours, and then go out and romp the **** out of it. Manually select 2nd on the column and run it up to about 5400 rpm's one time, and then put in D and drive it like you stole it for 10 miles.