Hello new to the board. I did a search and found alot on low oil pressure but nothing on High oil pressure. Excuse my lack of mechanic skills. I have a 75 FJ-40 with a Chevy 350 in it and the stock oil pressure sensor reads very high. Before I start the engine I can't even see the needle, but as soon as I start it the needle comes up very quick and at 1000 rpms it pegs the H in the guage, RPMs higher than a thousand and it pegs the right side of the guage way past the H mark. It runs well except it will not idle and as far as temp, the guage always reads right in the middle between L and H. Any advice would be greatly apprecaited. Almost forgot I am running 10-30 weight oil.

Can't tell ya about the stock gauge sicne I have a mechanical gauge for that, but it could very well be that the sender is incompatible with the FJ's gauge...

You need to rin a mechanical guage to really see what oil pressure you have. The electrical guages and senders must be a matched pair in order to work right. You can't just mix senders and guages and expect them to work.