P0304 - Piston Misfire (Cylinder 4). Why is this not going away? Acura TL 2001

[dandia89]

Initially I had misfires all all cylinders. Switched all spark plugs, now this one misfires randomly. TCS comes on intermittently with CEL. I notice when it's colder out and when I use remote starter the lights come on. It comes on so infrequently that I can not pinpoint it.


Things I've done so far:
-Replaced all 6 spark plugs
-Switched ignition coil packs (switched cylinder 4 and 6). No change
-Put in Seafoam into gas tank.

[carson blocks]

What I would do next is...

1) Compression test all cylinders. If 4 is low on compression when cold, no amount of further troubleshooting or throwing parts at it is going to matter.

2) (Assuming compression is good) If they're easy to get at, swap injectors with another cylinder. If the misfire changes cylinders, it's a bad injector. Also, visually verify no breaks, kinks, worn insulation etc. to the injector harness for that cylinder.

Edit: re-read your post about the multiple cyl misfires and mostly being fixed by the plug change. Maybe re-check your work and ensure the wire/plug boot is good on that cyl or swap it with another.

[AE92_TreunoSC]

Valves are issues along with the EGR port with that engine. A compression test might help you but sometimes gummed up valves lie to a compression test and only show to a boroscope or a leak down test.

Swapping injectors is the easiest thing to try next, beyond that you'll need to properly diagnose it.

[RickDaTuner]

its possible you may have damaged the plug on replacement as well.

Swap one plug into the #4 position taking note of where it was removed from.
then test again and see if the problem follows the plug.

When the remote starter was installed, was one of the coil wire used to tap in for Tach speed?

[dandia89]

Originally posted by RickDaTuner
its possible you may have damaged the plug on replacement as well.

Swap one plug into the #4 position taking note of where it was removed from.
then test again and see if the problem follows the plug.

When the remote starter was installed, was one of the coil wire used to tap in for Tach speed?

Thanks everyone for the suggestions, I'll update after I've tried all things.

How do I check if that was done? I didn't install it and am not familiar with my auto start installation

[mr2mike]

Find the remote start brain and trace the wires back. Then need acura wire diagram or look at the coil and see what color the wires are going into there. See if any match.

[forced_eg]

Ive ran into this problem COUNTLESS times... Hondas and acuras ecu's are horrible at pinpointing misfires. Even though you get a cyl 4 misfire, it really could be any cylinder. this is what you do, (if you have the mechanical know how to changing plugs then you can do this)

Remove the coil covers, start the engine (preferably cold) have a partner put the vehicle in drive with the foot on the brake and parking brake on (for a little bit of load to help you find the cylinder) now you carefully listen to the motor, unplug a coil one at a time and pay special attention for the engine stumbling.. plug it in and move to the next one. when you come across the cylinder that doesn't stumble then that is the one thats giving you the misfire... move the coil to a different cylinder, and the plug as well (don't rule out a faulty plug off the parts shelf too) and re-do the test... if the misfire moves to the cylinder you moved the coil to then theres your solution (which I'm betting)

If the misfire does not move them pm me and ill help you further.

[dandia89]

swapped the coils, took out injectors cleaned em and swapped them around. cleaned egr ports and the gasket on the intake manifold. no CEL in the past month, but it's been really warm outside so I don't know if I fixed anything