disgruntlednut

For some background: My car idles fine. Cold start, no problem. But for the past 9 months or so, every once in awhile, the car really struggles on a warm start. Shaking, rough idle, needs gas. Then after 30-45 seconds it runs just fine.

Yesterday, a check engine light finally came on (along with VSA/TCS lights). Checked the codes: Cylinders 2, 4, and 5 misfire, along with P1399 - Random cylinder misfire. I adjusted the valves and changed spark plugs 2 years ago, tried Seafoam (gas, oil, intake) last month. I have a couple of questions before I work on this....

1. I'd like to check the coil packs first, preferably one at a time. Is there any problem with just replacing one? And are the aftermarket brands ok or is the general recommendation to go OEM only?

2. With the EGR port, I cleaned the port out on the underside of the intake manifold when I adjusted the valves, but left what was built up on the motor. What's the best way to clean this? And is it OK for this crud to fall into the engine? (if that's where it even leads to).

Not the same engine, but this is what I'm referring to:

CL-S24

I'm getting the exact same issues. and the cylinder misfires.

disgruntlednut

Well, my (and mostly from what I've read from other forum members) suggestion is to start with checking the ignition coil packs. Super simple and won't take much time.

Start the car and let it warm up. While it's idling, pull one of the coil packs out. If it starts to hesitate or bog down, the pack is good. Then move on to the next one. If you pull it and nothing happens (still idling the same), it's likely your culprit.

Odds are, only one needs to be replaced, but it's possible that more than one has gone bad.

Tosh

I've had a couple of ignition coils go bad all of a sudden at ~110k, so I replaced all six with aftermarket Airtex-Wells from Rockauto.

But previously I've also had difficult warm starts and rough idle. Rough idle was cured with new IAC valve. And haven't had any difficult starts since reflowing the solder joints on the PGM-FI relay.

Everything there is to know about your Honda/Acura main relay:
http://www.tegger.com/hondafaq/mainr....html#blueline
http://www.tegger.com/hondafaq/mainr...mainrelay.html