# Please help



## kevinh430 (Oct 1, 2009)

So about 2 weeks ago my engine started running ruff so I went to the forms and read up on some reasons y. Then a few days later my check engine light came on so I have replaced common problems like the MAF sensor and the gas cap and the next thing I'm gonna try is the o2 sensor. And today while driving it the engine light started to blink so I took it home and now it's gonna sit there till it's fixed, please if this has happened to u let me kno how to fix it. Thanks for taking the time to read this and any info is appreciated


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## Falco21 (May 11, 2010)

Don't drive it. Parking it and leaving it is a very smart idea. There are multiple reasons for a flashing light as opposed to a steady light. You first need to hook up a code reader and found out the code its throwing. Post that in here, that way we can give you and exact reason why.

It could be a short somewhere, or it could be a misfire. I have also heard someone having an issue and it was a valve spring. You need the exact code being thrown or your just trying to find a needle in a haystack.


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## kevinh430 (Oct 1, 2009)

Ok I'll try and take it to autozone this weekend ASAP


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## Falco21 (May 11, 2010)

Usually they will allow you to rent it. I would try that. Try not to drive it with the light blinking.


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## kevinh430 (Oct 1, 2009)

autozone wont let me rent it since its the only one they have should i drive it over there, its about 2-3 miles from my house?


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## Falco21 (May 11, 2010)

If there is no other way for you to borrow one, then you have no other choice. Just pay attention driving it. If something feels off or you hear a knocking or such, pull over. You don't want to do more damage than could already be done. For all we know, it could be nothing anyways, but better safe than sorry.


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## Poncho Dan (Jun 30, 2009)

A flashing check engine light means its a "catalyst damaging event". Not "engine explosion imminent".

It's probably an ignition-related misfire. Raw fuel is getting down to one or both cats. If it stinks like sulfur, it's already too late.


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## Falco21 (May 11, 2010)

A plug or injector could cause it to flash as well. If not taken care of and ignored or treated lightly, it could turn out to way more than just a destroyed cat.


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## Poncho Dan (Jun 30, 2009)

It flashes because it senses an extremely rich condition at both the pre and post cat O2 sensors, so that throws fuel-related problems out the window. It's ignition.


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## Falco21 (May 11, 2010)

I have seen this quite a number of times and it is usually related to a spark plug or injector. I also was told that a solid light is emissions and can be driven, but a flashing light is a misfire/knock/etc. and should not be driven and fixed asap. The problem is if the cats are ruined or being destroyed, then there is something more serious causing it.


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## HP11 (Apr 11, 2009)

Never experienced that in my GTO but my daughter in law's Lincoln LS did. Her car also went into 'reduced power mode' along with the flashing MIL. Turned out to be a bad coil when I checked the code. (P0302-cylinder 2 misfire detected). Tested the coil, replaced the coil, cleared to code and it been fine ever since. In that case it was a coil but other things can cause a misfire. Acutally a fairly long list. Need the code to narrow it down.


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## Poncho Dan (Jun 30, 2009)

I'm not saying misfires are only caused by one thing, but a flashing CEL is not a fuel-related problem. It's in the ignition system or something is wrong with the engine mechanically, like low (or no) compression in whatever cylinder.

If raw fuel makes it down to the cat, especially in quantity, it will cook/glaze the catalyst. If you don't believe me, ground out a coil on a cylinder or two and see how long it takes for the cat to glow red.


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## HP11 (Apr 11, 2009)

I agree with you. I just more or less generalized in that post. A flashing MIL indicates that the PCM is seeing a 'Class A' misfire in the I/M readiness status area. That can harm the catalytic converter. During this type of misfire, if enough stray oxygen and unburned fuel is making it down the exhaust, it can quickly overheat a cat. Without the code(s), however, we really can only guess what's causing it.


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## 87GN06GTO07IRL (Aug 10, 2009)

Poncho Dan said:


> I'm not saying misfires are only caused by one thing, but a flashing CEL is not a fuel-related problem.


It easily could be a bad injector. Pull the clip off of one and it will do the same thing. A flashing cel indicates a cylinder misfire.


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## Poncho Dan (Jun 30, 2009)

Poncho Dan said:


> *A flashing check engine light means its a "catalyst damaging event".*


As per OBDII definition...


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## 87GN06GTO07IRL (Aug 10, 2009)

Never argued that.

<- See the silver one? Had a 60lb. injector stuck closed and the cel was flashing. Replaced it and was golden. Cats can overheat and be damaged from being run lean also. Maybe it's a little different because it's s/c but i doubt that.


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## t147 (Jul 27, 2011)

I've only ever worked at import dealerships and when I saw a flash, it was either extreme lean (almost always) or a knock that caused timing to be so far advanced or retarded the vehicle wouldn't even make it to limp mode. The last time I personally saw that light, it was followed by the wonderful sound of a rod knocking. Or a river of oil following me.

In my opinion, I wouldn't drive it. If you can't rent a tool from any of the major auto parts places or buy one. It's your call, if you feel there isn't a huge issue driving only 2 miles, I wouldn't do anything but let it idle other than to pull off and up a hill. 

IMO


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## markdavid (Nov 29, 2009)

Tow it to the Dealer !


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