Oil pressure

If indeed you have oil, check it, your oil pressure sensor is probably shot. It's right above the oil filter on the I6. If it has oil on it, it needs to be changed.

GMC 2003 to 2008 had this oil pressure problem. I bet you have about 160k - 200k miles on it. I've done just about every thing to my 2005 tahoe and finally found out what was causing the low oil pressure. Ready, put your seat belt on...I'm going to give you a list to check from cheap to the most expensive to fix this problem. Remember do the first and if not working go to second item on list. 1) change oil pressure sensor, it's cheap, look like plastic spark plug, only one, back of engine. 2) use thicker oil for high millage car 3) replace oil filter 4) replace oil pump filter screen 5) replace the whole oil pump assembly 6) Ok sit down for this one. This is going to be the most expensive. During the time period of model, the GMC had or used defected cam bearing. Cam bearing look like a semicircle flat piece of steel. One on top and one on bottom to hold the cam in place. When you open the head, I think 3 or 4 section needs the cam bearing. Well anyways the cam bearings had a v shaped groves in the middle to let the oil pass through while the cam is turning, this creates oil pressure. If you slow down or stop the cam doesn't turn much to create the pressure, but when moving the cam turns fast creating oil pressure again. Get the picture? Well the bottom line is your cam bearing is worn out, meaning no more v shaped groves to keep the oil flow going when idling. Well there you have it. That's #6, replace the cam bearing, half as much as engine rebuilt. If you love your car fix it, if not sell it. Good luck.

I have the same exact car/year/model and I have the same problem. What did you end up doing?

For me it was the oil thickness. My envoy was fine before the oil change. They put 5w instead of 10 and with the sun's heat it gave me this light. Went back to change it to 10w oil and it works fine now. Oil light back to normal. My truck has over 260,000

I drove my 2002 envoy with the oil sender unhooked and now it want turn over what's wrong with it I drove it a mile and it turned off the is oil trail the whole way????

Try changing the vvt cam sensor $26 at autozone the screen gets dirty and oil can’t get through it! It’s located on the front right upper side other the engine you will have to unbolt the power steering but not remove it. To get it out

@phc7764 - I think your analysis is right on but I am not sure about cam bearings. Are cam bearings split like mains? The cam on my 5.3 L are circular and pressed in with a special tool (usually by a machine shop). I suspect this Envoy is a 5.3 L vortec engine also. Replacement of cam bearings is usually accompanied by removal of engine and might as well do the overhaul as indicated. If the cam bearings are out, most of the other bearings will also be bad.

One of the coil packs went bad and that is why i has the low pressure oil light coming on!