ticking/chattering noise under passenger side valve cover...

Does anyone know if this is the valve lifter sticking. It started a couple of weeks ago but only did it occasionally after you started the truck up and would go away in under a minute. Now it seems to make the noise every time it starts and it is noticeable driving down the road for the first couple of miutes. Temperature outside does not seem to be a factor anymore.(first occurred when it was extremely cold outside.)

Hi,
yes, that could be a bad hydraulic valve lifter. Please have this checked out soon before there is more / permanent damage.
Take care, Eggert :bananasmi

Try Some Motor Flush This Will Help Remove Carbon Build Up And Allow Oil To Lubracate Better... Use Good Oil Like Castrol Gtx
An Engine Additive Might Help Also.

I use castol gtx. Also I have added a additive such as "restore" to the engine. The problem went away for two weeks and as of yesterday it is back. Also since yesterday my engine light is on steady???

Hi, can you read and post the diagnostic codes?
Take care, Eggert :bananasmi