Have a 07 5.3 with 220,000 miles. Noticed a week ago while coming to a stop oil pressure went from 40 at idle to 20 then back to 40. So today i change the oil and notice after a few minutes of ideling it started to drop from 40 to 20 again repeating this several times in a minute. All of a sudden a ticking noise starts and continues a few minutes then goes away and oil pressure starts to go back to normal 40 psi. What do i have bad lifter? Oil pump?

 

If you haven't all ready, I would recommend hooking up a mechanical gauge to it and checking pressure again. I have seen plenty of times where OEM gauges will fluctuate when a mechanical gauge reads steady.

 

If you hear ticking at the same time and it goes away when the pressure returns, its not a bad gauge. Could be a bad lifter. Did you check the oil for metal?

 

There was no metal in filter or on drain plug magnet. Ive also noticed i can feel a miss when ideling but no engine light comes on. Im about to pull valve covers and see what i can find. Motor is 100% stock not one problem in 220,000 miles just plugs and oil

 

You would be surprised how many things people hear when they see the oil pressure gauge reading wrong. The mind goes a little crazy when you worry about things. We had a car in the shop that the customer swore was starting to knock and he had no oil pressure. We hooked up the mechanical gauge, started it and listened. Pressure on the mech. gauge was normal and there were no noises. Turned out there was nothing wrong at all. My recommendation to hook up a mechanical gauge was just an easy first step to try.

 

WOW. I own a 07 5.3 with 224k. My ticking & low pressure gage reading sounds identical and used to be on cold starts. I would pull over, shut off the truck & restart and she would stop with the gage reading normal. (FYI- The pressure gage reading went to 0 psi maybe a year or less & I had the hard to get to valve replaced...all good, for a while).

Currently: Bad Ticking, pressure gage not reading normal, drops at idle and is not going away. NEED HELP, IDEAS, WHAT TO DO NEXT.

ALSO: Its definitely not my imagination. lol.