low vac

 

So I was thinking, if i had an intake leak it would effect it at idle, not when im on the gas. So it cant be low vac can it? It's a midrange and starting to be more high end misfire. I have god fuel pressure, new o2 sensors, new plugs, new wires, no arching. It idles fine too. It only has a problem when im driving it. Im thinking its the opti, icm, or coil. Am i on the right track? What should i replace first? Is there a way to check the icm or coil?

 

I don't remember exactly what the specs for vacuum are supposed to be, but I thought it was something like 17-22. 13 sounds pretty low to me.

Have you tested fuel pressure under load? You have to be able to read the gauge while driving at WOT all the way through the rpms to see if fuel pressure drops any.

You can test your coil:
http://shbox.com/1/coil_testing.jpg

Otherwise it could be your opti.

 

Yeah mine does sound a little low. I thought it was supposed to be 20 or so. But it idles fine.

What would be the symptoms of a bad icm? Would the opti have an rpm range it gets worse at like mine?

 

Usually the symptom of a bad ICM is a no start condition or cutting off when the car gets warm. You can get your ICM tested, but it's difficult to find an Autozone that carries the right connection you need. You could also do the ICM cooling mod and see if it helps any.

A bad opti can cause all kinds of symptoms; no starts, missing, hesitation, bogging, backfiring, etc.