My 93 Sport has a noise I can not diagnose. It sounds like a lifter tick that needs the valves adjusted. But, it ticks 3-4 times then goes silent for a second or two and repeats. The sounds speeds slightly with RPM increases, but keeps the same 3-4 ticks and silent throughout the RPM range. At first I thought it was a noisy injector but it seems to be coming from the drivers side valve cover area. Is there a way to adjust the valves on the 4.0's? Performance doesn't seem to be affected. The noise is slightly quieter the warmer the motor gets. Any ideas or help would be much appreciated. Thank you.