pcmhacking.net

My engine has a stumble at idle, I have a misfire coming down sparkplug wire 2+3.
This is confirmed because I put a light up inline sparkplug tester on the ignition leads. When the engine stumbles the sparkplug bulb does not illuminate.
So that cylinder does not get spark when the engine stumbles.

But I am just thinking, what if actually the injector is not spraying, and because of that the electronics are not switching inside the PCM to fire the sparkplug. So I might be looking for a faulty ignition circuit, but maybe the ignition circuit relies on a signal from the injector circuit to actually fire off the sparkplug.

Does that make sense.

I guess I can also check this with the oscilloscope to see if the injector on number 3 fires when the engine stumbles too.

it wont be a fuel issue, it will still spark if the spark side of things is working properly.

is it a v6 with normal coil pack, if so swap the coil to another set of cylinders and see if the issue moves to that pair, that should rule out if its the coil or plugs/leads.

Nah its a 4 cylinder and I have bought a new coil pack.

I have had what I think was a lean afr ignition miss/knock but that was under high load.

Could try swapping over injectors and see if the fault moves. Have you tried plugs/leads?

What vehicle /engine are you enquiring about?

new plugs and leads new coil new idle air control. it s a holden rodeo 4cylinder petrol 2.2L C22ne.