Chevrolet Repair: 99 Suburban Engine Ticking, lucas oil treatment, oil pressure gauge

Question
I have a 99 suburban with 140k miles, there is a tick that comes and goes. It sounds like it is in the valvetrain. I pulled the accessory belts off to be sure it wasn't them, the noise continued with the belt off. The tick goes with the rpm.  The oil pressure gauge has gone bad. The tick will go away for a few days or weeks then it comes back, then sometimes it acts real sluggish when it starts to tick. Its not a knock, clang, or pang, just a tick.

Answer
Hi Jared...you don't say which engine it is so i will assume that it is a 5.0L sounds like a bad lifter, maybe plugged and can't get enough oil. try an engine cleaner that you add to the oil. drive for a while and drain and refill.sludge build up will block oil galleries. once you have it clean try adding lucas oil treatment i find it is real good in bringing up oil pressure as it helps oil climb to parts faster that just oil alone.. hope this helps