Intermitten Misfires? [Archive] - Forum


View Full Version : Intermitten Misfires?

02-23-2006, 03:53 PM
I think my motor might be toast (LIM leak gone too long as the probable cause). Anyway, i'm getting intermittent misfires on Cylinder #3 (Why is it always the odd cylinders, why can't it happen to the even ones that are easy to reach?).

I've done the following:
-Put a new spark plug in Cylinder #3 (Delco Platinum Tipped to match the other 5)
-Swapped the Wire with one from my old set of wires
-Moved Coil Packs around

Cylinder #3 still misfires, so it can't be the coils, the weird thing is that everything is fine after starting the car for the first few minutes, but after about 5-7 min. the idle gets rough, and SES starts flashing (always a misfire on #3). After I let it rest and start up again, idle is smooth, then after 5min or so, rough idle (running on 5-cyl probably). Any ideas? I'm getting a ticking sound from inside the engine, so i'm thinking the motor might be toast, maybe something internal.

Would I throw a different SES code (I'm getting P303) if it was the injector? I put some injector cleaner in the tank to see if that helps.

I'd appreciate any tips, I still cant' figure out why it's intermittent.

02-23-2006, 04:08 PM
Clogged injector?

02-23-2006, 05:38 PM
Possibly, it's weird, it always idles okay on startup, and then once it's warm, I can feel the idle get really rough, if it does it long enough SES starts flashing, probably to let me know it's misfiring.

I dumped a bottle of injector cleaner in the tank today, so maybe that will help. I suppose I could always move the injectors around, but that means digging all the way down to the fuel rail :(

Any troubleshooting tips I can try without having to start going into the head?

02-23-2006, 08:24 PM
yea, it's a lot of work to swap injectors, but worse case scenario 5 bux for an injector seal kit Vs expensive motor work, I'd swap injectors to make sure.

02-24-2006, 09:07 AM
The motor is making weird noises, lots of them. Loud squeeking/ticking, sounds like it's coming from inside the engine. Not the lifters, since i've had that before, and an oil change w/5W30 usually clears that up. This is much louder and more pronounced.

Sounds like i'm gonna need engine work I guess? Anybody got any recommendations on where/how to be a used 3.4L engine? I'm guessing I should get one that's rebuilt since it may have internal damage from LIM issues if it wasn't rebuilt?

02-25-2006, 03:25 PM
I've got this same exact thing happening to me right now. Cyl. 3 misfire code. I'm on my way out the door to go buy new plug wires. I'll let you know if that clears it up.