P0300+ tach stopped working?

[Cali]

2 days ago my car threw a p0300 (random/mulitple misfire) code and also the tach started going crazy bouncing all over the place...yesterday the tach stopped working completely. also, the p0300 only comes on at highway speeds above 55 mph.

could the two problems somehow be related or it just coincidental?
i already changed the plugs, coils, wires, and the sensor on the tranny but the problems are still there. im guessing the tach on the cluster just stopped working but i can't figure out the p0300 so far. any ideas?

btw, this is my black galant, 2.4.

[RedGalant2k1]

Probable causes:

Ignition part failure.

Poor CKP sensor signal

Incorrect air/fuel ratio

Low compression pressure.

Timing belt jumped or broke teeth

EGR system failure.

PCM failed.

Thats what Mitchell says.

[dronesurfboards]

Its that JDM rear bumper....itll throw that code everytime....ill give you my usdm rear bumper and problem will be solved! you can thank me later

[RedGalant2k1]

I didn't have time to pull the diag procedures for the tach, but it seems to be an unrelated issue. But the easiest way to test the tach is swap in a new cluster. If the tach in that cluster works than you need a new cluster. If it doesn't work than you have a wiring issue.

[WarmAndSCSI]

Looks like your tach signal is independent of the ignition system. I would have thought the two problems would be related on the 6G72 because our tach signal comes straight off the negative side of the coil.

http://i159.photobucket.com/albums/t158/vancottt/4G64_ignition_diagram.jpg

Hope that helps...

[lucap100is]

that's my problem before, when they change my timing belt it keeps throwing that p0300 code at high speed. wires and plugs was replaced, they even switch the injectors. so, one of the TGC members recommend to check the timing belt. and he was right the timing belt is off. hope this will solve your problem.

[GOOSEY2099]

Ignition Failure switch took a shit, change that first.

[Cali]

Looks like your tach signal is independent of the ignition system. I would have thought the two problems would be related on the 6G72 because our tach signal comes straight off the negative side of the coil.

http://i159.photobucket.com/albums/t158/vancottt/4G64_ignition_diagram.jpg

Hope that helps...


well i tried switching out the gauge cluster and the tach still doesn't work and now the car is mis-shifting at times...the only thing i see left is the PCM from the diagram.

btw, the p0300 code hasn't come back on in 2 days since i last erased it.

weird.

[Cali]

Ignition Failure switch took a shit, change that first.

i'll wait and see if the light comes on within the next few days....or do you know if that is somehow related to the tach?