[Passion86]

Aright, I know I'm reviving an old thread, but I thought I better start here before creating a new one about the same issue. I installed an oil pressure gauge on a previous motor that blew, and put it on the new motor installed by warranty. I've recently started doing a lot more hwy cruising and noticed at 85mph or around 4600-4800 rpms my oil pressure would start to jump around erratically between 30-55 psi. If I backed off my speed to 83mph it was stable, and if I bumped it up to 90mph it again stabled out. I recently had my motor serviced for the valve spring recall, and asked him if he would check it out. He said he took the gear out of the front cover, cleaned everything up, and everything looked fine. Still jumps erratically at those speeds, so we determined it must be some kind of harmonic resonance and it starts to fluctuate like that. I still don't cruise at that speed though, as that's the speed I was going on the hwy when I blew the first motor. Which has had me thinking quite a bit about it.