I have a 2004 4x4 3.4L tacoma, that has had the timing belt changed recently due to a leaky water pump at 36,000 miles. After that was done I noticed a new sound when at 2500 rpm thru 3000 rpm. The noise is a rapid ticking sound that starts quietly at 2500 rpm then gets loudest at 3,000 rpm then quiets down again after about 3200 rpm. It doesn't seem to show up until the engine is warmed up and I don't have any check engine light, power loss or hesitation when driving. In fact, it seems to run fine.

My main question is, if valves that are outta adjustment will they chatter throughout the rpm band or can they be intermittent? Also would this be a symptom of the timing belt being put on wrong?

Thanks.