Cruise Control won't hold steady speed

[Billy Mild]

I'm looking for some other opnions on what could be causing my cruise control issues. I have tested the vacuum lines a few times and they all hold vacuum pretty well. I replaced the check valve under the plenum 2 times in the last year.

My issue with cruise is as follows: I set the speed to 80 MPH. I take my foot off the throttle, and the car will stay at that speed, occasionally the throttle will cut out, then re-engage, and repeat that process. It is not really predictable how often it will cut out and re-engage. I replaced the Cruise Control servo in an attempt to fix the issue. That had 0 effect on the issue. I can accelerate without issue using the cruise control Accel option.

I'm starting to think it is either my Abbott ERA box, or the Cruise Control module/computer.

Any suggestions?

[George Maz]

Same issue here.
Mine is repeatable. While cruise control is on (70mph), if I use my turn indicator to shift lanes...the cruise control cuts out, my dash board speed reads 53mph, all within a split second. Once the turn signal is released, the cruise cuts back on, car jumps to speed.
Keeping in mind the car actually only slows 1-2 mph, not 53mph. I've stopped using my turn signal when changing lanes with the cruise on, which I don't like. It's so odd, I wanted to post a video about it.

Maybe it's noteworthy, the car doesn't seem to like when I deactivate the cruise control from the switch, it bucks. A smoother transition for me is roll on the throttle a bit, then use the switch. Tap the brake also transitions smoothly if I'm decelerating, then switch off.

The ZR-1 cruises beautifully on a long highway trip, excellent fuel efficiency, panoramic view, ....all except the narrow butt seats! I'd have to agree with everyone's comments.

[George Maz]

Let me add, I also noticed that anytime & everytime I use my turn signal ...the speed number display changes to a lower number momentarily ...regardless of using cruise control. This is wacky, and I guess I'll be looking to buy a replacement turn signal lever soon.
It took me a while to notice this added condition, because my eyes are fixed to my surroundings and mirrors as I normally change lanes.

Does the problem stem from the lever, column, or speedo display? ...voltage drop or wire grounding out?
...guess I'll just not change lanes till I can get it sorted...:-D

[Billy Mild]

My speedo never stays a consistent speed. It is always going up or down.