Please help...misfire cylinder 3
#11
I have seen where a bad harmonic balance caused a issue with the crankshaft position sensor but that was a older 3800 with the groves in the sensor, Seems you tried or tested about everything that's related I wish you luck.
#18
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
Let's start with, what are all the trouble codes the car is throwing.... A LOT of money has been thrown around in parts in this rig, if we have all the codes the computer is throwing (and I mean the P numbers, not what a scan tool says it translates to), we might be able to scrape us some better info.
I know you said you replaced the ICM so my next blurb is pointless, but I'll share anyways. Those ICM tests at the parts store are limited. There is no heavy load on the ICM. I just went through this on my mom's car (3800 powered LeSabre). She had a horrible mis-fire on two cylinders shared by a coil. Long story short, ruled out the coil. Then had the parts store tested the ICM multiple times, it passed. Later that day I believe I should have had them modify their test. They connected at the main connector, used an alligator clip lead the first blade for the first coil and then an alegator clip lead on the second blade for all coils. I should have had them move that one clip lead to each coil position. Oh well, know for next time.
Using a inline test light (goes between the plug and the wire or the coil and the wire). Found very weak spark with it. Changed the ICM problem solved.
Using a inline test light (goes between the plug and the wire or the coil and the wire). Found very weak spark with it. Changed the ICM problem solved.