Ok so for the last few weeks I have been trying to find out what is chattering like a chipmunk in the front. I thought for sure it was my lifters. Well I took the valve covers off and thats another story but the lifters are all ok. No problems there. The RPMs are a little funky when its chattering. like a fluctuation of 100 rpm up and down. But the thing is it only does it when the truck is running down the road at about 2500 RPM? So now I'm not sure where to go and I really don't want to take it to the shop but if I have to I will. But I wanted your opinion first. What could it be? Ok rant over. tehe. thanks guys in advance.

 

it may have jumped time, and its the timing chain chattering

 

if it only does it at 2500rpm then how do you know its the lifters my just removing the valve covers?

 

Sorry I meant to say I thought it was the lifters so I took the valve cover off to see if it was and the lifters seem to be fine. So Im not sure where to go from there. I read on line something about a purge valve may be faulty???? ever heard of a purge valve on a gas engine?