This just started happening to me. Was just driving regularly and the needle on my type r tach just started to move randomly up and down for alittle bit then go back to where it was. I have a VAFC hooked up too and that reads the rpm's ok, but not my type r tach. Also the engine dies out on me sometimes when its just idling. No check engine light or anything! I have no clue as to what it could be. Also the engine from time to time seems to hesitate or like misfire or something, cuz it kinda jumps or lunges iono how to explain it, but if anyone can help me out i would appreciate it.
Thanks,
Matt

 

ive had that problem before with an older car...i cant really remember what the solution was. check the dist for corrosion all your plug wires....i remember it was something simple....make sure the dist is tight too

good luck...hope i helped a little

 

^TeRD racing he he jus playin

 

check spark plug wires and spark plugs and check fuel pressure regulator.

 

does the tach just bounce up and down or does the engine surge causing the rpms to change? if the engine is surging up and down then id suggest vacume lines if its just the tach going haywire id suggest wiring.

 

is it a stock or aftermarket tach? if its aftermarket itd be easier to trace if its bouncing and its just the tach there is no surging follow the wires from the tach. you will most likely find a loose connection somewhere along the line that is what is usually the problem when there is a bouncing speedo or tach.

 

if the engine is surging youve probably got a blown vacume hose causing pressure issues off of ur intake manifold, or a line is cracked or leaking off vacume pressure, sadly this happens to me often.