I had the Toyota dealership look at all of the recalls recently on my 2008 Tacoma V6 access cap pre-runner (90,500 miles). After they did everything, a week or so later, I noticed my speedometer jumping around +-5 mph as I drive. It had never done this before.
The cruise control also seems to be having an issue that is related to this problem. The surges that I'm noticing in the speedometer are affecting the cruise control as well. When I set the cruise, it seems to loose power and surge again and again with the jumping of the speedometer.
To be clear, when I'm driving without using the cruise control, I'm not loosing power, the issue is strictly with the speedometer. When I turn cruise on, the cruise seems to surge and loose power the same as my readings on the speedometer.
The problem is intermittent, it will do this sometimes and not others. The Toyota Dealer here in Abilene Texas says they haven't been able to replicate the problem. (and they don't know what the problem is). This was never an issue before I took it into them to have them do all the safety recall inspections. (one of which was to look at the spiral cable - that's what I think the issue may be - something not plugged in all the way)