No harm at all, but I would just do it. The more miles, the greater the chance of plugged ports. In HCH2 #1 (133K) there was a clear narrowing of the ports due to accumulation but no plugging. It took about 30 minutes the first car and barely 15 minutes for HCH2 #2.

The gasket is formed sheet metal. Just be careful you don't deform it as it will likely have a lot of caked soot too. Try to protect the coolant port from contamination.

Steve

 

Thanks, I'll look for that. I also read that a clogged Cat can produce back pressure and cause these random misfire symptoms. At least I'm on the right track now. If the ERG cleaning and plugs fail I will have the "expensive" OEM Magnaflow Cat by the 27th to try out.

 

I unplugged the ERG connector last night when I left work and drove 5 miles. I still got the "lurching" and misfires. Looks like I'll be cleaning everything & replacing the spark plugs on Saturday.

 

Not surprised. I'll repeat it again... if those are the stock plugs, they've been on borrowed time...

 

I was able to replace the front 4 spark plugs this morning. Starting from left to right, the first 3 looked OK. With the 4th one, the coil had some brown build up on it as well as the hole it came out of. Once the plug was removed it had the most white build up on it as well. I didn't have time to do the back 4. On my drive to work today I noticed an immediate improvement but when I put the petal to the floor to go up a hill I got the flashing CEL and noticed some lurching. I'm thinking the 4th plug from the left in the backside of the engine is also misfiring. Might take it to Advanced Auto to see what code its throwing now. I attached some pictures.

 

It's hard to tell from your pics, but I don't think those plugs look OK. There appears to be excessive gap and asymmetrical wear of the hook electrode. This is what my plugs exhibited. Please do a close-up side-by-side of the new vs. used plug looking at the end face of the hook portion of the electrode.

The coil and port build-up are likely due to moisture ingress.

The color of the plugs does not cause any concern.

Even with the "bad" coil I had, I never got a misfire related CEL code after replacing the plugs. Replacing the coil was a matter of trial and error via swapping between the two cars.

 

They do look a little toasty on the white part. I'll take a few closeups tomorrow morning when I do the rear 4 plugs. I didn't have enough time before work this morning.

As for the coil. Would that be coolant or just vapor that got in there? Think it could it be the seal on the top of the coil?

 

My driver's side rear coil was discolored with what looked like battery terminal oxidation on it as well as in the plug access port. The rubber seal at the top was deformed like it wasn't installed correctly. This car was born up north and shows a lot of evidence of salt damage, so I figured it was just general moisture ingress.

I figure if it was coolant, there would be other problems.

The coil in question wasn't the problem coil, so I removed the rubber seal off the problem coil and replaced it on the back coil. I haven't checked it since, but I've had no other indications of a problem.

 

I was able to get to the rear 4 spark plugs yesterday. Thanks for the tips S Keith. The Hybrid is running 100% better. No lurching and no flashing Check Engine Light to report. The back 4 plugs were Denso. I guess its a common thing to have 2 different types of plugs stock. I did have a small bolt snap while I was securing the last coil. Happened on the last turn. The coil is still secure but I have to get it fixed asap. Any suggestions would be appreciated. I attached some photos of the plugs and my mishap.

 

Glad to hear it sorted your CEL and running issues. From what I can tell in those pics, those plugs have been toast due to erosion for a long time just like mine.

Concerning the stud breakage, check here:

http://www.hondaautomotiveparts.com/...DER+HEAD+COVER

It appears to be a $1.91 Stud, item #3 in the figure. I expect it would be a relatively simple matter of extraction via an EASY OUT. I don't know what the official recommendation is, but I like to use left handed drill bits when I use an easy out. Of course, that assumes the stud isn't LH threaded. I recommend you buy a new stud to confirm thread direction first.

You could also weld a piece of steel to it and extract it that way, again thread direction should be confirmed.

There also might be loc-tite on it. If that's the case, heating of the stud would help greatly.

Alternatively, you could ignore it. This guy doesn't seem to have a problem after several months...

That thread also recommends another option... a salvage yard cylinder head cover.

The little acorn nuts on those make me paranoid, so I only tighten with a small ratchet using two fingers.