surging tachometer when driving
 

all of a sudden, my car has been driving like ----......
when the car starts up. it idles fine. when i start driving. i notice that the stock tachometer starts to surge around and bounce even though the rpm guages on my v-afc and avc-r are still reading correctly. when i add more than 20% throttle or so, if feels like the ignition is breaking up and the car is running horrible... the tachometer starts to surge in sync with the misfire feeling.

when this happens... the a/f guage is reading between rich and lean (as always). at idle the boost guage reads at 25 in/Hg. and it boosts and holds at 10psi.
i am not getting a CEL.

i checked for any vacumn leak. i also recently fixed a manifold leak.

what would cause the tach reading to be off?
what could be wrong? what should i check for? what more information should i get for anyone to help me out?

i'll paypal $5 for whoever can help get me on the right track. THANKS

Re: surging tachometer when driving
 

ignitor.

Re: surging tachometer when driving
 

as in ICM (ignition control module)?

Re: surging tachometer when driving
 

this happened to my car....i took off the cap on my distributor and clamped the wires firmly on the igniter or module im not sure which one it was.....the wires were really loose....this resolved everything. before i had done this....it did exactly what you discribed...hope this helps....

Re: surging tachometer when driving
 

I agree it's the ICM. It's about the size of a triscuit, inside the distributor. If I remember correctly, you have to take the coil out to gain access to it.

Re: surging tachometer when driving
 

yup.

paypal = mike.paquette@kmspeel.com
;D

Re: surging tachometer when driving
 

sorry for falling off the face of the earth.... but the forum has been blocked for me at work! anyways... i took the distributor apart and the ignitor had a huge crack across it.... i ended up replacing the whole distributor... the car runs great once again!

thanks for the help..... PAYPAL SENT! :y

Re: surging tachometer when driving
 

just change the whole dizzy, I changed my ICM and everything else in the dizzy started to go.

Re: surging tachometer when driving
 

dizzy

Re: surging tachometer when driving
 

ICM or cap and rotor, look at that rotor and the points in the cap, are there black arcing points? if not its the ICM