So here's the story. I recently purchased a 2001 Regal GS with a P0300 (random misfire) code. Misfires only showed on 3 & 6. I got it for a decent price because of the code and I figured it would be a simple fix. Misfire on 3 & 6... Must be a coil.
Wrong!
Let's step back to the original diagnosis procedure. Car idles great. ZERO misfires at idle. When I wind it up to 2k rpm, HPT starts counting misfires by tens on 3 & 6.
1.) I swapped the coils around. Misfires stay on 3 & 6. I figure it must be the ICM.
2.) I replace the ICM with a brand new Delphi unit. Still misfires on 3 & 6.
3.) I replace plugs and wires. Still misfires on 3 & 6.
4.) I swap injectors 3 & 5. Still misfires on 3 & 6.
5.) I tested for 12v at #3 injector with the key on. Lit a test light nice and bright.
6.) 12v test light on the #3 injector connector barely pulses. Very faint light. However, it is the exact same intensity as #5.
Not sure where to go from here. Maybe a compression test? What that will tell me? Again, zero misfires at idle, no excessive blowby, and it's still on a stock pulley.
Rapid fire: What to I check next?
7.) CASE relearn done. Still misfires on 3 & 6 (P0300) with and additional P0303 (misfire on #3) code.
*Edit. CASE relearn fixed it. Read on for details.
