1- Fuel, temperature and oil gauges stay at the last reading in my car also. Voltage, speed and tac go to bottom of gauge, tac should read 0 with key on, if I can remember I think it's actually near 10 RPM w/key on engine off on scan data due to digital to analog conversion in PCM..
2- 650 RPM is close to stock idle setting.
3- I think the oil sensor is left top of engine behind the EGR valve (see shbox site for exact location). Pull the wire off, and observe pressure, then short wire to ground gauge should move between 0 and high reading, my US gauge reads 0 lb to 80lb yours at 100 must be metric KPA. Could be the sensor is plugged up with dry oil. I searched but could not find what the correct ohms-to-pressure resistance range of the oil sensor should be. 650 Idle should be 10-40 lbs (us readings) of cold oil pressure depending on how old engine is.
4- I don't think stock with just a tune and cat removed will make 340 HP at rear wheels, stock is around 275-280, maybe 300 w/a good tune unless other work was done to it.
I'm Bob 1994 Z28, A4, cam, 1.6 RR's CAI, LT's, stall, cat back. Custom tuned. 2007 GMC Envoy, tuned. 2015 Kia Sorento, bone stock.
Last edited by bobdec01; 06-08-2019 at 11:16 AM.