potential speed sensor issue

89 civic, making a wierd "flickering" noise behind the speedo dial. needle is steady, but the noise concerns me. if trying to drive 55, the
engine's been stuttering a bit. nothing serious, but if you have the stereo off, you can hear a brief "ptt" change in the exhaust note every few seconds. fine at higher speeds & below 40.
so, is this engine behavior a symptom of speed sensor problems? there's no code, yet.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.