ttiwkram

Hi, All.

Please bear with me on this one, as I have limited information right now (I'm at work, and my wife just called me to describe the problem).

Background: 2005 Altima, 2.5L, gave code P0420 about two weeks ago so new Magnaflow stainless catalytic converter was installed. All has been well, until...

My wife called this morning and said the car ran like cr@p when she started it (after it sat overnight at a temperature that's roughly freezing plus or minus a degree or two). The Service Engine Soon light was blinking. She let the car warm up for a few minutes hoping for improvement, but no change.

About half an hour later, she had to drive to class so she gave it another shot. She said the car started right up and ran perfectly for the entire 15-mile trip.

I'll throw the code reader on it when I get home, but in the meantime I'm trying to imagine what the cause could be. Has anyone else experienced this and, if so, what did it turn out to be?

Thanks in advance.

Mark W. in MI

smj999smj

A "flashing" MIL occurs when the ECM detects a problem that could be detrimental to the catalytic converter. Most often, these are ignition related problems. Could be something like a bad cam or crank sensor, bad ignition coil or a leaking spark plug tube seal that is causing a short between the coil boot and cylinder head, etc., but the first step would be to see what stored codes exist.

ttiwkram

Well, it's the darnedest thing...

When I got home last night I checked for codes. There were none.

Apparently a flashing SES light means a misfire, which of course would dump unburned gasoline vapor into the catalytic converter and eventually cause it to overheat.

Anyway, after the initial episode my wife and son put about 75 miles on the car yesterday without further trouble. I drove it to work this morning (25 miles) and so far, so good. There's nothing more fun than an intermittent problem, eh?

I guess for now we'll just keep an eye on it, and maybe look into performing the idle relearn procedure (I disconnected the battery before removing the alternator to get enough access to change the converter, so maybe the car forgot how to idle).

Thanks for the reply!

Mark W. in MI

Outkast

Coil pack are very common failure on those when you get the flashing MIL. I always recommend replacing all four cause if one is going the other ones are right there with it

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