Hi all,
I’ve been having this misfiring engine for a while now. It sometimes doesn’t trigger a CEL and sometimes does. Seem to happen on start up or when turning and hitting gas. Also noticed it more, when running low on gas. It goes away when I pull over and restart the engine, sometimes after a few tries.
I have recently changed the pcm and bought 2 new ignition coil racks over the past 6 months. The issue still occurs. Any advice?
Since you've already changed the PCM and replaced the ignition coil packs, here is a few other potential causes:
Fuel System Issues: Given that you've noticed it happens more when running low on gas, it could be related to the fuel delivery. Consider the health of the fuel filter or a weak fuel pump that might not be supplying enough pressure, especially when you're low on fuel. You could test fuel pressure at the rail and see if it's within spec.
Spark Plugs: If you haven't replaced the spark plugs recently, they could be worn or fouled. Even with new coils, faulty plugs can still lead to misfire issues.
Vacuum Leaks: A leak in any vacuum hoses can lead to misfires and unstable engine behavior. It might be worth inspecting your vacuum lines to make sure they’re intact and connected properly.
Throttle Position Sensor (TPS): If the TPS is malfunctioning, it could lead to erratic engine behavior, particularly under load when accelerating or turning.
Crankshaft/Camshaft Position Sensors: If there's an issue with these sensors, it can cause misfire codes and lead to erratic engine behavior. It might be worth testing them.
Check for Codes: Even if the check english light isn’t consistently on, it’s a good idea to run a diagnostic scan to see if any intermittent codes show up that might give more insights.
It might also help to keep an eye on the fuel level and see if you can recreate the situation when the misfire occurs. If the issue persists or becomes more frequent. If it were me I would hook it up to a scanner that can read live data so you can get an idea of what's happening in real time.
