Alright this is the scenario in my lq9 with 95k miles. Cold start my oil psi is about 35 idling and increases with acceleration as normal. But after about 20-30 min of driving the idle psi is at 15-20 and fluctuates slightly. The oil psi still increases with acceleration but does not reach the psi it does prior to 20 mins of driving. There is valve train noise on the rear drivers side. It is a fast paced clicking sound. During the first 20 mins of driving the clicking is god awful from 2-3 rpm, but after 20 min of driving the sound is much less distinct but still only in the 2-3 rpm range. Haven't had a chance to pull off the valve cover and check for rockers or push rods. I was just wondering if anyone else has dealt with the same problem.

Edit: No metal in the oil.

 

no metal in oil, are you sure? i would bet that the oil has a slight glisten to it

 

When i drained it i shined a flash light through the flow of old oil and no glistening or sparkles. And also ran a magnet through the oil drain pan and nothing either.

 

when it in the bucket and you shine the light on the oil did it have tinny tinny sparkles in it. if you dont have any oil in the car right now i would remove the oil filter and cut it open with a band saw or some other device. that will tell you for sure if you have a spun bearing. if you do you will see the metal flakes from the bearing in the filter

 

Do you have stock rockers, or do you have adustables? I have had two instances. One where I had a bad lifter, or if you have adustables the poly locks get fatigued and come loose which would cause one hell of a noise.

 

That doesn't sound like a bad lifter. More often than not, the lifter noise will not be rpm dependant. Have you taken the left side cover off?

 

No i haven't found the time to check rockers or pushrods. Also haven't had time to pull off the valley cover to check for unusual wear on the cam. But as of now the noise has stopped except for cold starts and during first few min. of operation. So i am just going to drive it until something gives, then the plan is to completely rebuild the entire car.