i have a 2001 suburban LS 4x4 reading about 283,500 miles now. I have only owned the truck since 192,000 miles, so previous service history foggy. Anyway, Cold start....normal oil pressure of 45-50 psi idle. As the truck warms up from driving, pressure falls off, will goto down to Zero if i idling at a light or stop(yes light comes on, will make lifter tap if i dont catch it in time and hold the gas pedal to raise RPM's above idle) or will fluctuate while driving until it gets to full operating temp which at that point truck will have normal idle pressure of 40 psi and will hold a 60 psi at 2k down the interstate. I am thinking the o-ring in the pickup tube, but it could also be the pressure relief i guess hanging... I have changed the oil religiously at 3-5k using KN filters and 5w-30 synthetic

I am just looking to see if others have had a similar problem and what they did to correct it before i start just changing parts.

 

I have a thread posted here about my 93 Suburban now at 350k. Wear and tear the likely diagnosis. By changing to 20/50 oil I am able to keep my hot idle psi at about 10. Whats your current oil consumption?

 

Rednucleus -

Use about a quart between changes, it may have alot of miles on it, but it will run like a scalded dog if i need it too.