wat the fcuk???

[randOmcLamsheLL]

1) 3 codes..
53: Exhaust Gas Sensor Circuit (right)
33: Exhaust Gas Sensor Circuit (left)
34: Detonation Sensor Circuit
2) my speedometer shoots up to 55 and stays there
3) my oil pressure gauge doesnt seem to work much either
4) temp gauge seems to be acting up. normal driving no problem, on the highway if im buzzing at 3K in 5th gear the temp goes up a lil past 9:00, then i slow down and drive at 3K 4th gear and it goes down, pulled over no smoke at all. also checked the coolant and its good, took the rad cap off and ran the car to get any bubbles out and its still doing it. WHY?

EDIT: also forgot to add tht i replaced the ecu, checking the fuses tomorrow

[DMeN Z]

Codes 53 and 33 relate to o2 sensors. Prob gave out or 1 of the 3 wires broke at the connector.

Code 34, most commonly occurs because the circuit isn't complete (break in the wire). Can also mean your sensor died (least common) or the ECU is detecting knock (?). How's the mpg? (I imagine horrible with the possible combination of bad O2 sensors and running in limp mode)

Speedometer itself probably crapped out, Speed sensor circuit code would point towards an electrical fault (bad speed sensor in trans, circuit break)

Oil pressure sensor most commonly goes out. Should get another set of Z ears and have them listen for knock. May relate to your code 34. If you don't hear bottom end knock or loud lifter tick- you're fine. Just replace the sensor on your next oil change.

Cooling and temp should be better at highway cruising speeds. I've seen AZ brand replacement coolant sensors mess with the gauge. Could try testing it (the temp gauge) by switching out with another coolant temp sensor and check if the same repeats. Check your oil also just in case (for a milky color or "frothy" visual).
Next time it does that, turn your heater on full blast to help radiate some of the heat until you isolate the problem.