Rough Idle. Ignition Problem? Bad Tank of gas?

[kellogg_racing_]

OK gentlemen,

Finally got the ol Honda up and running again after my fight and utter loss with the storm drain curb. Now last night (after running great for a solid 2 weeks and the whole day) i start it up to leave from my friend's house and it starts and idle very rough. I don't think much about it, figuring once I put it in reverse and drive a few feet it'll clear its throat so to speak. Well it didn't. To the point I pulled back in my friend's driveway and popped the hood. The engine was shaking more than normal (not violent, but still), but the most noticeable problem was the sound of the engine. It sounded like it was only running on 3 cylinders. Best way I can describe it is it sounded like my engine was running an extreme camshaft profile. I've uploaded a video of it to youtube to help understand. The other thing is when I drove it home (only about 7 miles or so) occasionally it would return to normal, smooth operating circumstances. Then it would go back to sounding "cammed"

This all leads me to believe it's an ignition problem, a bad tank of gas (being I just filled up saturday afternoon) or a combination of both. Any suggestions, ideas, anything. We're going to do a complete tune-up regardless as it needs it (plugs, wires, cap, rotor) and treat the gas (fuel injector cleaner and heet-for any water in the gas from the possible bad tank).

Here's the video link:
http://www.youtube.com/watch?v=4F-7Z3On568&hd=1
Be sure to watch in HD to get the full sound at the end of the video.

Thanks in advance guys!

EDIT: I forgot, also smelled EXTREMELY rich. This is mainly what led me to believe it may be ignition related, and the cylinder that's not firing is just getting gas dumped in it. No CEL either.

EDIT 2: Updated video. Lets you hear the possible misfire more clearly
http://www.youtube.com/watch?v=N2YjX7pHoFU

[esskater892]

check for an engine code. i had a rough idle and it sorta went away. but it still wasnt right, and i noticed when i started the engine light flashed like telling me i had a code so i checked and it was the dizzy cylinder position sensor. replaced it and its solid now.

[kellogg_racing_]

It's not throwing codes, like I said. I already checked.

[kellogg_racing_]

Also might be something with the emissions? (Like EGR Valve) Please help guys...

[sin2k5]

I recommend new spark plugs and spark plug wires -- just a basic tune up. It's good to do even if it doesn't solve the issue.

Bad or worn spark plug wires can do this. It's happened to me and it's happened to a friend of mine (1 year old wires). The car will idle rough and want to shut off after you rev it up. Sometimes it would run perfectly fine.

Lack of wire insulation will create ignition problems. Sometimes, you will even have arcing/grounding -- losing power. Let the car run, get a spray bottle, and mist over/around the plugs by the valve cover to see/hear any sparks jumping (may not be noticable). Mine sparked by the small breather hose from my valve cover to the intake pipe. The plug was grounding onto the small hose clamp (sparking) before reaching the spark plug.

Then consider cleaning out carbon deposits (EGR valve, Use Seafoam through the manifold, idle air control valve etc.)

[kellogg_racing_]

Bump. Today we disconnected the cat and started it; still ran like before. Took EGR Valve off and cleaned it, still ran as it did before. Did an EGR Vacuum test (where you manually open the EGR valve and see if the car stalls) and the car showed to response to the EGR valve opening, despite our confimation of its physical operation while it was off (the valve opens and closes with response to vacuum like normal). We are at a loss. We doubt it's anything ignition now, because it only acts up once it is warmed up (IE: emissions are allowed to operate). Please help...

[deevergote]

Did you clean the EGR ports as well, or just the valve?

Does your CEL work? I once had a 3 day exchange with a guy on here about how he had no codes whatsoever... and it was because his CEL bulb had been removed by the previous owner. He was throwing 5 codes when he replaced the bulb! I know it sounds stupid... but I have to ask.

If the problem occurs after the car has warmed up, then it's possible that it's an ECU or sensor issue. The "warm up" phase is when the ECU is running in open loop mode. Basically, it is running off of pre-programmed tables, and not sensor feedback. Once the engine reaches operating temperature, the ECU switches to closed loop mode, in which it uses sensor feedback to adjust the air/fuel mixture.

I would try another ECU, and see if that changes anything... or throws a code.

[kellogg_racing_]

Did you clean the EGR ports as well, or just the valve?

Yes, both on the valve and on the manifold runners.

The CEL light bulb makes sense for sure; however, when you first turn the ignition on and all the instrument panel lights light up, it does too. So I know the bulb is good. I have read though, that you can still get a code even if the check engine light does not stay on? We were going to check codes despite the no CEL during operation.

I was just reading another member's "running rich / rough idle" thread and he mentioned the MAP. Are there procedures for checking that? I need the voltage chart for comparing to a vacuum gauge...

[kellogg_racing_]

My dad and I have checked so many things and unplugging them and see if it makes a difference. We're almost positive it's a fuel problem (from being rich) so I'm going to map out the whole ecu pinout, find a description for each pin, and make a list of elements that relate to fuel in anyway and make a list of them and check them. After that, I'll look at ignition if we still cannot find anything...in the mean time everyone please keep the suggestions coming! If nothing else, it keeps me thinking!