Installed and tuned the device. The car seems to drive differently though and has me worried. I am going to go over my wiring in the morning when it's light again.

Is there a high probability it's in my head if everything (device, tuning capability, speedo, odo, etc.) works correctly? The EPS light came on during my 1st adjustment while the car was idling but went away and didn't come back. The oil light flickered twice (only 80% it was even the low oil light since it merely flickered) when I went on a rough road but oil level is fine. That's never happened before though. I can't see how messing with these specific wires could impact how the car drives and if I did tap the wrong wires either the speedo or device wouldn't work correctly.

*edit: FWIW I tapped the 5v yellow/blue wire, not the 12v wire, since people seemed to have better luck with that one.

 

That's a bit odd that the EPS and oil light came on. The EPS light will come on if you idle for too long at too high an rpm. Sometimes when we do work on the car and we get things too heated up, the idle can drop lower than usual and this can cause momentary low oil pressure. You should at least verify by GPS that the speedo is working close to accurate.

 

Interesting, it idled for a few minutes but not longer than normal traffic conditions.

The speedo seems a little "slow" at very low speeds but it is working correctly. I put my GPS in the car and was about 7-8% high. I held down the adjustment '+' button for 6-7 seconds and tested it again; at that point it was only 1mph off at 40mph. The adjustment directions that came with the yellow box worked exactly as stated. I'll put another 20-50 miles on it and see if I end up stranded in the process.