MIL code 62 - miles not stored and crappy gas mileage


New member
91, AW4, 33's @ 28psi, regear to 4.88 and new speedo gear verified by GPS for proper speed on dash.
I currently only get one code (62) and it's possible it's wiring or an ECU going bad, I think. I've had issues from the start where the speedo needle will not work and then suddenly come on. The sensor on the tail housing of the 231 spins pretty freely and once I shot some silicone in the gap to stop it from spinning, the speedo needle works consistently. Could that code get throw if there is a bad connection to the speed sensor in the transfer case and I just pulled an old code? I cleared the codes and drove home with no speedo needle issues so maybe I can pull the codes again today and see if it's back after 100 miles.

Also, gas mileage is between 9 and 13 (on a good day) mpg. I was hoping after fixing the gas leak in the tank, new FPR, injectors, NTK O2 sensor and heater wire fix, I would get closer to 16 driving 60mph for 30 miles or so with a little stop and go to go wheeling, but I don't.

Looking at the video, it appears the ECU is seeing the right data out of the O2 sensor and it at least switching from Lean to Rich implying closed loop, right?

If I need a new ECU, I can get one for a 95 for $35 but I don't think it was a sport edition nor do I see the stupid infrared module above the rear view mirror in the donor. I'll need to get one with the security module, right? Or is there a way to delete it since I don't use it anyway?

Ignore O2 sensor here, I unplugged it to test if ECU was recognizing it

Click for video
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