Here's what's going on... I went to the track a few weeks ago and almost every time i hit 8K rpms my tach goes crazy bouncing all over the place. I took out the cluster and found the speed sensor wire cut and spliced together with another cut wire sticking out... so i replaced it with a clean wire which helped some because it used to freak out at 7 K and now it does it at 8K. Should i sauder the wire ? Can i run a direct wire from the msd... help.....

 

you should solder it together. I do alot of tach installs and I always hook it up to the RPM wire from the ecu and it works really good.