My '96 T100 3.4L shows low oil pressure when fully warm and idling at a stoplight. If i give it any gas at all, even just a few hundred RPM's, the pressure goes up to almost to halfway. I only get low oil pressure when the truck has been run a lot and it is more prevalent in the hot summer days than the cold winter days. The engine is all original with only 129,000 miles on it.

The oil pressure never completely drops off the gauge, but it hovers on the lowest reading sometimes until I get the engine moving again.

These trucks take 5W-30 oil correct? Can I try using some 10W-40 to see if that increases the oil pressure slightly? Any other suggestions?

10w30 wont change it at operating temp, its normal for the oil pressure to be low at idle.

after 2 3.0's, one with 122k and the other at 155k, both did/do the same thing as yours. I am in upstate NY and use 20/50. If you are really concerned get an accurate guage and check it out...

Check your manual, pretty sure that is with the norm. The 2nd and 4th line are where it should be when not at idle (if memory serves correct).

So there is no need to worry about the engine running out of oil pressure? It sometimes reads right at the very lowest possible on the oil pressure gauge. I didn't know if that meant there was 0 psi or if it is just enough to lubricate while idling?

I find myself bringing the engine up to about a 1000-1100 RPM idle just to bring it up and make myself feel better. I don't need to do that?

Mine hasn't read like I intuit it 'should' since it broke in. It's entirely common for the dash gauge to read low. I wonder if it might start reading lower in relation to the valve cover gasket fading (or something else; it's a vehicle - things get old and wear out) as it seems mine has read a little lower since I noticed oil weeping out a little at the back end of the covers, but it should not be taken on its own as an indicator of a catastrophic engine failure. I would not (don't myself anyhow) feel a need to keep the engine raced a little at a stop the way you describe.

Unnerving, isn't it? Yet it's a Toyota truck special, they all do that. Low reading oil pressure gauges is the norm with Toyota trucks.

I did run 10w-40 in mine once, made a faint difference, but not much.

This is normal.

When I bought my first T100, it had the same behavior and only 62K miles. I made the replace the sender and gauge before purchasing. It did the exact same thing when new sender and gauge.

Joel

Good to know, thanks to all of you for putting my fears to rest. I'll ignore it.