Speedo mis-calibration

[Marty G Cars]

Anyone have experience on calibrating an Autometer 5" electric speedo. I had previously performed the proper calibration on the same style speedo in my 68. However, when I was recently driving my 69 home from the speed shop (needed new maps for the FAST), I thought it's about time I calibrated this speedo too. The car has been driven a few times during the build but without the proper calibaration on the speedo and now the odometer shows like 3000 miles when the car actually has less than 200. Here are my questions.

1) When I attempted to calibrate the 69 speedo, I mis-remembered the process and ended up pushing the wrong sequence of steps. Now the thing is way out of whack. I then referred to the Autometer website, wrote down the steps and took the car out again, but now that did no good either. The steps are first hold down the odometer button while starting the car (this should peg the needle to the highest position which is 160 in my case. The next step is to drive to the start of a measured two mile distance, stop the car, (keep the motor running) and push the odometer button again which should then move the speedo to the halfway point which is 80. The final step is to drive the car to the end of the two miles and stop, then push the odometer button. This should calibrate the speedo properly (and did so on my 68). I don't know what I did but now this process will not calibrate the speedo on my 69.

2) Is there any way to adjust the odometer mileage to reflect the actual miles. The car does not have 3000 miles, more like 200 but since the previous drives of the car were with the speedo being not calibrated (sometimes showing that I was going 150 when I was actually going 40), the mileage is way overstated.

Any help would be appreciated!

[Texas Hotrod]

My Autometer speedo uses the same sequence. Hold the button while starting. Stop at the measured 2mile, push the button, drive the distance, stop and push the button again.
One thing I noticed, is when I was driving the measured miles, the odometer was showing the reluctor count from the speed sensor. Actually my meter is installed on a motor cycle. I used a Chevy speed sensor mounted next to the rear sprocket to give a speed signal. It registers the sprocket teeth as it rolls down the highway. So, as fast as the numbers were counting up on the odometer, it was counting each tooth as it went past the sensor.
Try the reprogramming again and see if yours gives a sensor count while in the calibration mode. If it doesn't you could have a bad meter.