Noise at 2,000 rpm

[Evilimports]

Alright, I know it's next to impossible to diagnose a noise over the internet, I'm just looking for some good logic based ideas of what the possibilities are.

There is a horrible ticking noise coming from the valve cover (already have revised lifters) when I let off the throttle around 2,000 rpm. It won't do it under heavy load and it will do it constantly around 45 mph on a flat road. Really hard to reproduce at idle but can get it to do it for a second. Noise waits a few hundred miles every time I have the cams off. I was convinced it was a weak auto tensioner but the noise cam right back that time (did not have the cams off).

Guessing its a bad rocker arm or a valve floating. Any ideas on what els it could be or how to verify?

 

[tds]

You probably have a bad lifter, since it goes away when cams are removed, allowing the lifters to extend st that time.

 

[Evilimports]

Nice idea, would make sense. But the first time it started making the noise it still had the original lifters but the engine had been rebuilt. I replaced the lifters and the noise was gone for a while and then slowly cam back. If it was a lifter issue i would think it would be an oil supply to that lifter since its done it with 2 different ones

I should mention that it "ticks" hard enough to set off my knock sensor. After every shift right as I let off the gas it ticks/knocks really loud and my engine light flashes on.