slight knock on decel and at idle

[white6.0]

noticed about a week ago truck started knocking slightly idling and when you are deceling the truck has 240,000 thousand on the stock engine. tried putting it back to stock and does not make a difference. might be time for a new truck.

 

[STROKER]

It could be something as simple as a injector causing a miss, also have you taken the oil cap off while its idling and checked for blowby?