I'm working on a 2000 3.8 manual trans.

It came in with a dead miss on cylinders 3 and 6. Given that these two share a coil, my first thought was a bad coil. I removed the coil and checked the signal on the two terminals under the coil.

I had continuous power on one and a flashing ground on the other with the engine running. I installed a new coil and still had no spark. I swapped the original coil (that I thought was bad) with the coil for cylinders 5 and 2 and started the engine. 5 and 2 fired just fine. I also ohm tested the spark wires for 3 and 6 and they are good.

So, now I'm puzzled. The ignition module seems to have what it needs to activate the coil, and the coil isn't bad yet it doesn't fire.

To add to the mystery I did try a new ignition module. With that installed the engine ran horribly. As if the timing was WAY off. I reinstalled the original module and now I'm back to running smoothly, on 4 cylinders. No spark at all on 3 and 6. So I don't know if I bought a bad module, they gave me the wrong one (it looks and installs identically), or there is something else going on.

Any ideas?

 

Either a bad wire connection from PCM to module or a faulty PCM - bad driver for cyl's 3 & 6.

 

I have seen bad New ICM before. Since the engine got worse with the new ICM I would still think that is a suspect area. Just checking for voltage is not a good way to check ICM. Without a scope what you are seeing will not mean much. I had a coil fail on a 3800 and the car barely ran.

 

The drivers for individual coils are in the ICM, not the pcm. The pcm only supplies timing signals. The ICM determines the individual coil timing.

I would try another new ICM.