TIMING ISSUE-what controls advance

hey guys. to be specific, what controls the timing advance during operation. I no the computer and ignition modual work together to control spark and timing advance. What I need is were do these devices get there input to determine the propper timing advance. one of these devices is bad, but i can't figure it out.My 96 :banghead: 2.3 quad4 is advancing way to far and effecting drivability. I hooked a snap-on computer uo to the car and drove it, this is how i no. You can see the timing advance to far and then feel the car shake. Strangly, it only does this 50% of the time, otherwise drives normal. thanks for any input you guys can provide

your problem is most likely related to a stretched timing chain and/or worn out timing chain tensioners on this engine, not the actual advance programming in the pcm.

To answer your question, the crank position sensor, cam position sensor and knock sensor are the three main components the PCM uses to set/adjust timing advance.

thanks for the reply. the tensioner and chain were already replaced around 10,000 miles ago and the crank position sensor. So i gues i'll replace the knock and cam position sensors next. maybe that will do the trick..thanks again