Blinking Check Engine Light?!

[Wease]

The "Check Engine" light has been lit in my Mountaineer for some time now, at least over a year. I know what the problem was, I know what code it has been throwing. The passenger side, #1 O2 sensor was bad. I'm just lazy and the gas mileage and performance didn't seem to be affected at all.

Anyway, last night, leaving a friends house, I started it up, right away I notice it seems to be running a bit rough. It always runs smooth, I have had no problems ever with my Merc. It sounds like it's running on 7 or less cylinders, but I thought little of it as I pulled out. I get going down the street, my wife notices the sluggish sound and I agree with her. We turned down another road, started to gain some speed, suddenly it gets a bit worse, then the Check Engine light starts blinking! I knew that was a bad thing, so I turned around and went back to my buddies house. We looked it over, it was still running rough, then all of sudden, it got better and was normal again. I drove it the 42 miles home, and it was fine. Finally got to replacing the O2 sensor today, and drove it a bunch. No more sluggish feeling no more Check Engine light.

My question is this: What might the problem have been last night? I thought maybe bad gas, maybe it was pinging really hard and it was pulling timing. But could bad gas be enough to cause it to run that rough, and actually set the Check Engine light off to the blinking mode? I'm still kinda concerned about it...

 

[cjpwalker]

Owner's manual says a blinking check engine light means a severe misfire, and possible catalitic converter damage could occur if you continue to drive for long periods of time.

 

[mexi]

if your check engine light was blinking. you had a dead miss . thats what causes the blinking. you need to invest in a tune up . plugs wires etc.

 

[Wease]

if your check engine light was blinking. you had a dead miss . thats what causes the blinking. you need to invest in a tune up . plugs wires etc.

Just did all that, not 10K miles ago.

 

[mexi]

wierd well blinking light means a dead miss .i dunno ? if it dosent do it again and is running fine i wouldnt worry bout it

 

[Wease]

Yeah, it was misfiring for sure. But it's been fine since. Hopefully it was just a freak thing, who knows...

 

[mexi]

good luck with it . just put a new motor in mine :fire:

 

[Mbrooks420]

Hopefully you didn't ruin the cats. by driving for a long time with a bad 02 sensor.

 

[Joe Fast]

Check the wires for damaged insulators. You may have an arc occuring inconsistantly. This happened to me with a non-Ford product and was easily repaired.


JOE

 

[Brock94]

The focus on the ignition is a good idea. I had the exact same thing happen with my V8 Durango-- I pulled over and turned off the engine. (blinking CEL, running rough-- just not the 02 sensor code) Since it sounded like it was missing, I pulled and reinserted each of the plug wires to make sure they were tight. Problem solved. That was over a year ago and I have not had any trouble since.

 

[Wease]

Well, the damn check engine light is back on this morning. This thing pisses me off. I'm gonna have to get the codes checked again tonight...

 

[Brock94]

Did you ever replace the O2 sensor, or is it doing the rough engine/blinking CEL thing again?

 

[Wease]

Did you ever replace the O2 sensor, or is it doing the rough engine/blinking CEL thing again?

I replaced the O2 sensor yesterday, the one the readout called for. The CEL never came back on at all yesterday, I thought I had this problem licked. Then my wife calls me today, says the light came back on. It's just on, not blinking. It hasn't blinked since Saturday night. It's been running fine, it just appears I either have something else wrong, another bad O2 sensor, or that one is bad already... :fire:

 

[Mbrooks420]

Which o2 sensor is it? The one behind the cat?

 

[Wease]

Which o2 sensor is it? The one behind the cat?

No, the readout said "Bank 2 Sensor #1". From what I was told, that is passenger side, first sensor. So I replaced the one before the cat. I'll be heading up to the autoparts store again soon to get another scan to see what the problem is this time...

 

[Wease]

OK, just got back. Now the code is "EGR Flow Excessive", so I bought another EGR valve. This code was actually thrown last time, but the guy at the auto parts store said that it was probably being thrown because of the O2 sensor being bad. Who knows. It will be in tomorrow morning, so I won't know if this will fix the problem until my wife gets home tomorrow night and I put the new one on. I hope this does it...

 

[rasustaita]

Check the insulation on the wire lead to the O2 sensor. It could be worn down to the wire causing the CEL to blink on/off. It happened to me, taped up the wire and secured it from rubbing on the frame.