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Random/Multiple Misfiring But Only When Idleing

A

Adam66402

Messages
21
Engine misfires on idle only slightly ***, Power is fine when driving and the eml will only come on flashing if left idleing for 5-10 mins ticking over. Done full service including spark plugs. The OBD Reader says P0300 Multiple / Random Misfiring and also shows cylinder 2 and 4 misfiring. Like i say when driving the performace is 100% and only notice once it flashes on idle! Has anyone experienced this or have any ideas? I am wondering about the Injectors as i can hear ticking near them but will swap them over tomorrow. Cheers for any help!!
 
THOUGH*

Injectors tick.

Try swapping coil packs around to see if the misfires move.
 
Swapped the coil packs over this evening and still the same result with the EML showing cylinder 2 and 4 misfire! I will have a look at swapping the injectors in the morning to see if that changes anything!:rolleyes: Otherwise i will have a look into the inlet manifold gasket as there has been a few people with that leaking causing misfire issues..
 
Same issues on my EP3. Go to a garage and check your compression. In my case I had a slight bent valve on cylinder 3.
Car was shaky slightly on idle,eml on, on diagnostic showing engine missfire, but drove fine.
 
Hi, Thanks i shall get the compression checked on wednesday like u say.. I can then rule out cracked head, head gasket, cylinder or valves.
 
So.. I have booked the Civic in later this afternoon for it's compression test (Fingers Crossed!!)
I have also swapped around the Coil Plugs this morning but it still shows the same result of misfire 2 and 4.:rolleyes:
 
I have been to the garage today and it was confirmed that cylinder 4 has low compression which must mean that i have a burnt valve! Am guessing it isn't going to be a cheap fix..:( ...
 
Low compression could also be worn piston rings or cylinder bores too.
Or even the cam timing out ever so slightly.

Hope it's a cheap repair.
 
You could test for stoo's cam timing theory by doing your compression test a few times with your engine in different positions... Just turn it over on the starter and try again.
 
if the timing would have been out then you could tell as the engine would run really bad. Usually when you have one burned/leaky valve, you get multiple engine missfire from all the cylinders, however the cylinder that has a loss in compression will log more missfires than the other ones. A proper snap on diagonstic scanner will show the number of missifires on each cylinders while the engine is running.
 
Thanks for your help guys, I managed to source a Honda technician that has taken a look and it seems the chain has moved 2 teeth and streched a little! So in away at least it hasn't damaged the valves (Luckily) as it could of really gone bad if left! So it's a New chain, Tensioner and the chain guide. Then the valve clearences are being done to be on the safe side..
 
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