Misfire under load - No codes

[thegoat54]

Hi everyone.

I have a 2004 Alero with the 3400.

Getting a misfire under load. Notice it mostly when approaching a hill and trying to maintain speed.

It is getting worse, and yesterday it misfired to the point where to Check Engine Light was flashing. I can't get the engine to throw a code though to help me out.

I replaced the plugs a couple months ago, but not the wires. Those are original. I'm thinking the wires?

Any help is appreciated.

[RalphP]

Wires is what I'd be checking next, yes.

However - if you can find a dark enough place, what you can also do is take a spritz bottle filled with tap water, and while the motor is idling in the dark, spritz the spark plug wires.

If you get a "blue fire" around the wires, they're certainly bad

Also, treat the coil packs the same way, in case you have a bad coil pack.

Further, if you have an Android device with Bluetooth, it may be worth while finding a good ELM327 Bluetooth OBDII module and installing Torque Free on your cell phone / tablet so you can see why it's blinking the "Check Engine" light.

With the age, though, replacing the wires may not be a bad PM type thing irrespective.

Two things - 1) Don't forget to use the proper boot grease. 2) Do them one at a time so you don't forget where each one goes.

RwP

[MMGT1]

^^ what he said! Good tips there... You can also check resistance of the coils to ensure you haven't lost one. They should all read between 5-7K ohms each when tested