Prius 2004 Cylinder 1 Misfiring

fabgo · 02-22-2006, 08:02 PM

Twice in a row, when I've taken a trip to Yosemite in my 2004 Prius, the M.I.L. light has come on. When I take in for service, the scantool says cylinder one is misfiring. The first time around they found some corrosion / water damage as specified in some TSB, but this time around they can't figure out what's going on.

The only thing I can think of is that both times it happened when 1) it's cold and 2) the car is at altitude. Anyone else experiencing something similar?

Frank Hudon · 02-22-2006, 08:14 PM

tell them to change the spark plug in #1 hole. You probably had water in the spark plug tube and it shorts out the plug. Irudium plugs don't really like miss firing and quite often fail shortly after a few misses. The other thing that happens with miss fires is the cat's can't take the load of fuel dumped in them and they over heat and could have a core meltdown, plugging off the exhaust. This needs to be addressed as soon as possible.

galaxee · 02-27-2006, 09:24 PM

the ignition is a COP (coil on plug)

suggestion: swap coils, see if the misfire moves to the other cylinder.

well, maybe it's a suggestion for the tech if you're not comfortable tinkering under the hood.

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02-22-2006, 08:02 PM	#1
fabgo Join Date: Jul 2004 Posts: 5 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Twice in a row, when I've taken a trip to Yosemite in my 2004 Prius, the M.I.L. light has come on. When I take in for service, the scantool says cylinder one is misfiring. The first time around they found some corrosion / water damage as specified in some TSB, but this time around they can't figure out what's going on. The only thing I can think of is that both times it happened when 1) it's cold and 2) the car is at altitude. Anyone else experiencing something similar?

02-22-2006, 08:14 PM	#2
Frank Hudon Senior Member Join Date: Jan 2004 Posts: 4,144 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	tell them to change the spark plug in #1 hole. You probably had water in the spark plug tube and it shorts out the plug. Irudium plugs don't really like miss firing and quite often fail shortly after a few misses. The other thing that happens with miss fires is the cat's can't take the load of fuel dumped in them and they over heat and could have a core meltdown, plugging off the exhaust. This needs to be addressed as soon as possible.

02-27-2006, 09:24 PM	#3
galaxee resident lab rat Join Date: Mar 2005 Location: boilermaker territory Posts: 9,676 My Car: 2005 Prius Model: N/A Package: #5 Thanks: 0 Thanked 94 Times in 37 Posts Friends: 26	the ignition is a COP (coil on plug) suggestion: swap coils, see if the misfire moves to the other cylinder. well, maybe it's a suggestion for the tech if you're not comfortable tinkering under the hood.