truefire04

got a question for you all... truck is a 99 gmc sierra with a 5.3 with over 170,000 miles on it, i have noticed that while at idle, like at a light or stop sign that the oil pressure gauge will fluctuate, but while driving its fine stays around 40 psi, regular driving and rises with throttle, sometimes it does it and sometimes it doesn't. so my question is, would it cause the truck to idle funny, if the sensor/ sender is bad?

FFDP

iTrader: (2)

I think you mean idle not ideal but I get what you're asking.

You could hook up a manual oil pressure gauge to see what the oil pressure is really doing at idle but it's not super uncommon for it to jump up and down 5-10 psi. It can change with idle dips or if the ac compressor clicks on and off and that will raise and lower the rpm. Aslong as it's still over 20-30 psi while hot, you are just fine.

truefire04

yea i meant idle. that would make since, since i just recently had the ac fixed and have been using it more now. and it just slightly drops under 40 psi when it does it. i have autometer gauges that i need new senders for... guess i need to get on the ball and get them. do you know where a good place to get a water temp from. i know i can get the oil pressure from the oil cooler block off plate, it just needs to be drilled out.

truefire04

ok, so i replaced the oil pressure sensor since it was bothering that it moved so much, now when i first start the truck oil pressure sits between 40 and 80 psi after i have driven it a while the pressure will read around 40 psi or just a tad shy of 40 psi, but the question is. now when i turn the truck off the gauge does not return to zero it stays at the 40 or so psi mark is this normal, the old sensor did not do this.