bowdoe

Hi guys.

2 months ago my car started misfiring and then lost like 2 cylinders completely and I had to drive it around like that for maybe 30 kilometers.
Checked diagnostics, it showed nothing, check engine light didn't turn on either.
I changed the ignition wires to brand new ones, my mechanic changed the ignition coils to used, tested, working ones and changed the coil connectors to new ones too. Plugs have around 5000 kilometers in them.
Car has been fine for like 800 kilometers now, maybe more, but yesterday on startup it started misfiring again, then it slowly cleared up and was fine for another 100 kilometers. The same day after it was parked for an hour, I started it again, and during startup it misfired for a sec, cleared up, and then it was fine for a whole day again. Today it had no problems at all. Diagnostics still show nothing, no check engine light either.
Currently we're running out of ideas, I read through all the forums and they told me nothing that me or my mechanic haven't checked. I know that the car is a bit sensitive to the battery being good, but it is perfectly fine, ground wires look good too.
Another thing is that it was misfiring when the engine was still hot, on cold starts it never did it.
Car has ~382k kilometers on it. Any help would be appreciated.

Thank you!

dwoods801

Even if it isn't generating a DTC when misfiring, you should still be able to pull up the Air to fuel ratio and see if it's an issue with fuel pressure, usually will show a lean A/F ratio, if it's an issue with the spark then your going to find it's rich if your A/F ratio is ideal then it's likely an issue with the internals or rotating assembly. You could have a problem with the valves or something like that. If you have a good OBD2 scanner, you should be able to track numerous parameters while the engine is running. If you can identify any lchanges while its misfiring and then smooths out. you'll be able to recognize what your problem is.

Oro

I had some mild misfire codes on the 09. Nothing terribly palpable, but codes generic (300) and randomly alternating specific ones (moving around). I:

- removed intake from filter box to throttle body.
- Cleaned throttle body well
- new pcv valve
- installed intake carefully with all joints and hoses checked.
- Put a bottle of Regane in the tank (like Techron, has PEA additive)
- ran 1/2 can of SeaFoam through each side on the intake runners.

Codes/misfires have been gone a while.