I noticed yesterday when i was leaving a store my car started pecking not knocking but like a pecking and a pinging noise, no check engine light on oil pressure is normal. So i went over the street and got some oil "was the first thing i done anyways it said good so i added a quart, it didnt stop so i said i better take it easy and get it to the house only being like 5-6 miles away i started driving the speed limit a lil under plus or minus, about halfway there the noise stopped. I thought it mighta been sludge "i know this time i used a differ oil same weight called mobil 1. Anyways the pinging comes and goes in the morning when its cold it starts up. It's comen from the back of the engine kinda in the middle, I'm guessing maybe a lifter or dunno?

 

Pinging in its classical definition means that you have a problem with detonation which is the fuel air mixture igniting before its supposed to a very bad thing that can do a damage. Pecking im not sure as you would have to describe it better maybe make a video of the sound.

 

check your knock sensor. Passenger side of block.