OK I got back to Florida after a few months--connected the battery cable to my Odyssey van and it runs real ruff. I disconnected the coils one by one to see which cylinders are out and (I don't know the firing order) the cylinder on the front right--front far left and the rear far left made no difference with how it runs. So I have a 3 cylinder car. So I ordered 6 coils and 6 spark plug --installed them--runs the same. Anyone know of some common conditions that would cause this in Odysseys? And because I just connected the battery I can't pull any codes. Anybody's brain power would be appreciated. Thanks.

 

Disconnecting the coils (for coil over plug) for a power balance test is good
But, it doesn't tell you if the coil is bad or the injector or fuel pressure or valves or gaskets or etc
It only tells one which cylinders need further testing

If you have animals in the area then they could have chewed on the wiring??
Just don't know until more tests are done
Start with the basics
Fuel, Air, Spark, Timing, Exhaust, Compression, all the fuses, vacuum leaks????

 

Hey Thanks for chiming in on my issue. I don't belong to forums so I apologize in advance if I don't follow the protocol. I know I need to do more testing but I thought that even though I have been working on cars for close to four decades I am not to stupid to see if someone has intel on a vehicle specific problem that occurs frequently that would point me in the right direction. Yes I have had issues with my last van that had rodents living rent free under the hood. And I had to solder new wires in to repair the damage. I don't see any evidence of nesting but the wiring is on my check list of things to test out. Thanks again for your input and I will keep posting results from my findings!

 

your ody may need a valve adjustment. each 110k miles the valve lash needs to be checked. this happened to my Honda Fit. at 230k never adjusted valve lash, ran rough at idle, . adjusted valve lash and engine smooth as original.( also changed plugs and coils prior to valve adjustment, did not fix rough idle. )

 

Thanks for the reply. My Ody has 142k. The only thing that causes doubt in your theory to me is that it was running fine when I left it here in FL and ran on 3 cylinders when I reconnected the battery upon my arrival last week.

 

OK I purchased an HEI spark/ignition tester, Basically an adjustable spark plug. I have a strong spark at all the affected cylinders. The arc jumps across a 3/4 inch gap which should be sufficient for combustion. So I ordered a valve cover gasket set and will be adjusting the valves when it arrives. Even if that does not cure the issue with 143k it is a good maintenance task to have under my belt as I proceed with my once over for this newly acquired van. Fingers crossed!!

 

did more research, if your engine has a vcm which shuts down the rear cylinders when in cruise mode, a sensor can get locked into the ivtec mode mostly after driving and over rev the engine in netural by mistake.

 

Thanks for spending the time researching for me.I'm not sure if my van has that feature but the cylinders that have the issue are 6-4 and 1.

 

OK Gasket set arrived took it apart adjusted the valves went around once then went around again and rechecked and adjusted a few better to my liking. Got it back together and still runs rough. Better though as before I would not drive it ( this from a guy that was driving my car sparingly with just the emergency brake while waiting for parts to arrive) now I took it around the block and it does drive but not at higher RPM's.Engine light is on and blinking and then stops TCS light comes on then sometimes goes out.I pulled it in the driveway to see if I could count the number of blinks the CEL was doing but it would only blink while driving. While in idle in the driveway it would start surging back and forth from 1000 RPM to 1400 RPM. Need to check the wiring more thoroughly to rule that out. Down to injectors or pcm.

 

cold idle surge usually idle cut off unit, warm idle surge usually exhaust surge valve need cleaning.