When its running it is making a pinging sound and it runs rough.The ping is coming fron the intake manifold.There isent any check engine lights on or anythingIt does it ever time its running weather the truck is hot or cold and i was told i could be that it needs a higher octane gas or a EGR valve or a knock sensor.I cleaned the EGR valve but it dident make a diffrence.If anyone knows what it could be could you help me out...THANKS
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