Just got my headgasket done and rebuilt the turbo on my 88 supra. After having it done for about a month now, I've had low oil pressure issues. At first it just seemed all over the place, I would look down while idling at a stop light and see that I'm almost at 0 on the gauge, but then I would start to go and the pressure would build. I think that I've got it down now to where it is normal when it is cold (30 to 40 psi a little lower at idle) then it seem to be dropping when the engine warms (assumingly when the oil is warmer and thinner). The final nail for me was when I drove, pretty much all day, from Bellevue to Auburn, to Seattle then home to granite falls. I rode it kinda hard, I had to keep up with one of my buddies, and i heard some clapping, it was pretty faint, but It's got me convinced that it is some type of oil pump related issue, not a gauge issue or anything.
At first I thought that it could've been debris from my headgasket job, but this doesn't seem likely to me because of the above experience, with the long day of driving. So I'm left believing that it is a issue with my oil pump.
I haven't done too much reading up on the oil pump in the 7mgte, I plan on doing that.... now
Any advice or trouble shooting tips would be greatly appreciated.
INFO: 1988 Supra 7M-GTE 190K fresh headgasket job and turbo rebuild in mid february 2011.
Thank For any help guys.