Ignition problem
 

Hi, I'm fairly new to these forums
I apologize if this has already been posted.
But my mother has a 2004 Monte Carlo LS, 3.4L with 108,000 Miles on it currently
It has been starting pretty hard for a little while now it cranks but takes a little while to start
And recently it has been stalling while she is driving and stopped at a red light or so.
We just replaced the spark plugs with NGK iridium plugs, Spark plug wires with AC delco and the three ignition coils with united ignition coils
All from Rockauto.com
We put everything back together and it started right up no problem
But there is a clicking sounds almost like a misfire as well as a irregular idle.
Was wondering if anyone has any input or troubleshooting help
Thank you very much!
Oh the fault code i got before I changed everything was a P0300

Did any of this exist before changing plugs, wires and coils?

FYI - GM original coils do not fail often and no need to change them unless they have failed. My experience with coils is to stay with GM coils and I shy away from the part store replacements.

The clicking noise makes me wonder if you have an electrical arc happening. Get a water bottle with just water, at night, run the car at idle and mist the water, you may catch flashes of light where a wire is failing. Make sure all the plug wires are firmly seated on both sides before you start.

Did you use heat sink compound between the coils and the ignition control module? This prevents overheating & arcing between the contact surfaces. Could be a bad ICM too. In case you don't know, P0300 is "Engine Misfire Detected" on more than one cylinder.

After we put in the new coils,plugs,wires we checked the ICM and it was bad so we replaced that.
Just tried starting the car just now and it took awhile for it to start had to hold the ignition key for a bit
then when it finally started it was rough idling and sounded like it wanted to stall.

Could be the Idle Air Control motor (IAC) you can take it out and clean and lube it, but there fairly inexpensive ($20 as I recall) to see if that makes a difference.

If these problems (misfiring) began after the work you did, re-check all the new parts and the connections of anything you messed with during the process.
And just because they are new coils and ICM does not mean something was not bad out of box.

I will keep checking, but the car just started right away no problems or anything this morning cold. Took it for a drive to get hot shut the car off for a few minutes and tried to start it up and it was a hard start took a few seconds and once it finally kicked over the rpms were not staying steady going down to almost stalling then back up
Thank you for all your help!!