Random Misfires

[BassnKY]

I am trying to fix my son's 2000 LaSabre, 3.8L, 106K miles. I am getting the dreaded P0300 (Random/Multiple Cylinder Misfire) . Here is what I have done to date. 1 coil test was borderline on the bad side - replaced all 3, EGR would not read correctly - replaced, replaced all plugs & original plug wires. Replaced fuel filter. Checked MAF & TPS -both good, fixed bad o-ring on idle air valve. Fuel rail pressure good. Intake 18.2. I am at my wits end.
Any ideas? All help is greatly appreciated!!!!

 

[Bloberov]

I would check the Ignition Control Module (ICM) connection, and or replace the module itself. I had random misfire recently on mine and it turned out the ICM was faulty.

 

[BassnKY]

I have found several checking procedures. How did you determine it was the ICM?

 

[Bloberov]

I have found several checking procedures. How did you determine it was the ICM?

I had checked each coil and all were in working order creating spark. Decided to go ahead and install a new ICM has been good ever since.

My ICM failed only on one coil bank, so I did have spark on 2 out of 3 coils.