Hi all just after some help if anyone can my saph is running msd wasted spark and ive got bored of the rev counter running double speed.So i purchased an spa tacho fitted it and it works fine but when the signal wire is connected the car has got a terrible misfire!! doh!!. ive spoken to Stu at msd who has suggested a couple of things but they both involve either attacking the ecu or cutting into my braided loom which until ive explored other avenues im reluctant to do, so if anyone has fitted one of these and knows how to over come this problem please could you advise?! all help appreciated Alex.