98 civic starts running rough then CEL

98 civic, 289000kms, 5spd, non-vtec.

Driving home in some snow tonight, car started running rough, as though on 3
cylinders.

CEL started flashing. Code was P0302 at first. My code reader cleared it,
then the flashing CEL came back. Read P0300, P0301, P0303, P0304. No other
codes.

I recently replaced the cap, rotor and sparkplugs (all from dealership). I
am using Bosch plug wires (I know, but they have a lifetime warranty
apparently), so I replaced the wires with new bosch wires (warranty as
mentioned).

While changing the wires, I decided to check the condition of the sparkplugs.
They all looked fantastic, but I did notice that they were all pretty loose!
Not falling out loose, but not tight.

Tightened them down, seated the plug wires, and all seems OK now. I also
reset the computer as the idle was a little low after completing the work.

My question is: Did I solve my problem here, or is this a sporadic problem
perhaps with the ingitor? Anyone else out there have this issue before?

t

 

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Somebody peed in your gas tank ? Seriously, you may need to replace or
at least back flush your fuel filter and maybe add some methyl hydrate.
Was it COLD where you were? Fuel line icing sounds like that too.

'Curly'

 

If there is ethanol in the gasoline, there is no need to add fuel line
deicer. The ethanol will remove any water in the tank.

Instead of adding methanol (grain alcohol, methyl hydrate), I would use
iso-propanol-based dry gas. It is better for the fuel lines and other
rubber parts and more effective, because it dissolves in gasoline better.

Jeff

 

There is a known issue with the CR-V for exactly this problem. The CR-V has
basically the same engine as the Civic.

The CR-V's problem is exhaust valve(s) that have receded into their seats.

Check your valve clearances.

If possible, also do a cylinder leakdown test to check for burnt valves.

 

in winnipeg, so it was -14C.

Most fuel here is 10% ethanol.

As mentioned, the problem seems to have cleared itself. Just wanna make sure
its not something else that is sporadic.

t

 

crv is b-series - most civics are d-series [apart from the si].

more likely the valve itself is getting hot enough to cup around the
seat - that's fairly common on other cars. valve seats on hondas are
high quality and in a highly conductive aluminum head - they rarely get
hot enough to actually recede.

technically, leakdown is for rings. simple compression is for leaking
valves. and if they are, got to take the head off to replace.

 

leakdown works well for valves as well, you only have to listen where the air
is leaking (air intake or exhaust system) to detect your problem at TDC.
Doesn't tell you what cylinder though.

Now that the plugs are tightened up and I got new wires on it, it seems to be
running like a top.

Thanks for the ideas all!

t

 

Oops. I was thinking of the Integra.