see if i can get some help here, i have a 90 dsm with a 91 ignition system and ecu. still has the 90 cluster but the tach doesnt work, i reed the way to fix it but thats not the problem. the car is misfiring a little, would the the tach not working cause the car to misfire?? because the ecu isnt getting the signal?? or could it be a normal reason why its misfires like fuel or spark related. please any help will be appreciated.