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I did a full rebuild on my 2001 6.0 lq4. Had no issues whatsoever over the past 2 months or so, just out of nowhere last week I noticed when at a stop and the truck drops to idle. The oil pressure drops by half, but then becomes normal once driving again. I’ve replaced oil pressure sensor as recommended by a friend and nothing has changed. If anyone has had similar issues please let me know what you did to fix it. Thanks
When you rebuilt it, did you replace the screen beneath the oil pressure sending unit? If you did, get it out of there. They clog up and cause problems with the readings. Not saying it's definitely the problem, but there's a good chance.
When you rebuilt it, did you replace the screen beneath the oil pressure sending unit? If you did, get it out of there. They clog up and cause problems with the readings. Not saying it's definitely the problem, but there's a good chance.
I never saw anything in there, I’ve been told that they’re in there but I’m not seeing anything and I’ve stuck a pick in there and nothing came out. What would you do to pull it out if it is in there?
There's always a chance that the pickup tube O-ring got damaged on install and finally split. Not likely, but it is possible. The retaining bolt could have came loose as well. First thing I'd be doing is installing a mechanical gauge at the front driver's side oil port and verifying pressure there. You want to eliminate any electrical issue first.
There's always a chance that the pickup tube O-ring got damaged on install and finally split. Not likely, but it is possible. The retaining bolt could have came loose as well. First thing I'd be doing is installing a mechanical gauge at the front driver's side oil port and verifying pressure there. You want to eliminate any electrical issue first.
I completely agree here. Electric gauges act up all the time mechanical gauges tell you exactly what is going on. Go get you a equus gauge from oriley and hook it up to the front driver oil port and see what it’s doing. I would go ahead and run it inside so you can monitor it idling and when you are driving it.
To anyone that is/was wondering what the issue was. My oil pump bolts backed themselves out, and was causing the oil pump to back off the block. Not sure how the did, has I did torque them correctly. I’ve attached some photos to show the damage.
I’m thankful that it wasn’t a bearing issue, like what I had originally thought.
Glad you caught it before things got worse! Thanks for returning to let us know the solution to your problem. It may help someone else in the future. In regards to your bolts coming loose, those don't take much torque. If I were you, I'd have my wrench calibrated because there's a chance it isn't reading correctly. Also, if you only have one wrench, I'd get one specifically for those lower torque value bolts ( such as a 5-80 lb. ft. one ), as larger wrenches are inaccurate at lower load values.
What was the damage? Sprocket doesn't looked wrecked, the Pump might be.
Pump is is cracked, can’t pick it up on the picture. And the sprocket is worn down with lots of scratches and dents. It is also allowing the oil pump to slip a little bit in some spots. Just taking some precaution and I’m just going to replace most of it.
Oil Pressure Issues. 
