Help!!! What's happening? Flashing check engine

2003- with 129,000. Automatic.
So last week the check engine light came on out of nowhere. Strange. It came and went over a few days. Today, I was on the interstate and the light began to flash, and the car lost most power and would only go about 30 mph. Once I pulled off the ramp, it would barely idle. Anyway, I pulled out my tool kit, removed the battery cable... Viola! Ran like a champ for 3 more miles, check engine came on, lost power, then blinking. Sitting here waiting on my buddy to get me, the car is NOT running hot, good oil pressure... I smell something cooking a little. Is this the cat stopped up? I did notice that when it was blinking, if I went to 1/2 throttle lets say, it would whistle/belt squeak a little. I wonder if that's the poor thing wheezing because its constipated??? Thoughts? I put napa coils on it 5800 miles ago with new plugs also.

Don't run it if the CEL is flashing...it does that so that you will stop driving. My first guess would be coils, but you just replaced those. However, they can and sometimes do fail, even new from the factory. You need to get the codes read to really find the problem.

Similar thing happened to me this week. This may not be your problem but mine turned out to be the intake shutter valve failure. In 2005 there was a recall for the intake manifold (if u can remember) rather than replace the manifold they replaced the shutter valve (cheaper I guess). Anyways it was warrenteed for a year after. It's been less then 6 years and mine just malfunctioned causing the power loss and cel. I was sure it was the maf sensor or the coils after some research because those two would cause similar indications. I'm replacing the entire intake manifold and doing a full tuneup (just in case). The maf checked out okay. I can let you know the outcome on Saturday when I get the parts installed. Also check to see if you had the recall repair cause it will save you $$$$. Good luck

Mine is a 2003 and its already at the shop.

Mopar92 said:

Mine is a 2003 and its already at the shop.

Click to expand...

So is mine...just trying to help

Yeah. Thanks for the reply though. Good idea...

Update: got the part early and all installed (as aforementioned). Test driven and results are great so far! GL Mopar.

Hopefully it didn't mess up your precat...

tweety2300 said:

Hopefully it didn't mess up your precat...

Click to expand...

Are you referring to the misfiring that occurs with this problem affecting the precat? Can you please elaborate because I understand the basic functionality of 4stroke cycle and purpose of components (I.e intake/exhaust manifolds), however I am amiss with precat damage possibility. I can only image that if that were the case another indicator would code. Thx

The precat does the same job as any other catalytic converter on any car, including even our own second catalytic converter. A catalyst is any substance that affects the rate of a chemical reaction. The catalyst used is a thin layer of platinum (partly leading to the expense of converters).
The converter, converts the partially burnt hydro-carbons (carbon, carbon monoxide) into a safer gas,... carbon dioxide, by heating up and adding more oxygen to the carbon till it becomes CO2.
Most converters also convert nitrogen oxide (NO) into safer nitrogen and oxygen (N and O2).
The precat on our car uses a super thin and delicate mesh of some platinum coated material. The catalyst needs to be hot to do its job so the precat heats up and starts working very quickly. But if that precat gets a dump of raw fuel on the paper thin honey comb mesh it gets way too hot and very quickly it melts.
Regular catalytic converters (like our second one) have a heavier honey comb mesh that can deal with greater amounts of heat. Even if they have carbon and some raw fuel on them they can eventually heat up and burn it (convert it) without instantaneous damage. That is why we can still pass emissions using just our second cat and a non-fouler. It is also a good idea to rev your car up close to red line once in a while after it is fully warmed up,... it helps to blow the crap through the honey comb mesh and clear it self out a bit.
I spin my car up to redline a couple of times a month for that reason,... I get nervous doing it though,... that's when you're more likely to send a rod through the hood.

Or in the short basic layman a terms, when your car misfires it doesn't burn the fuel, that fuel gets into the precat which destroys it.

If this happens you will get p0421. A new one from Mazda is $1,000. But if you don't have super strict emissions you can deal with it for $10 with a non fouler and get a rotten egg smell every once in a while, or get an aftermarket header to delete it with the non fouler. You won't get a cel and will still pass the sniffer test but if they check to make sure the Pre cat is there you will fail. But with just the non fouler they won't know the difference

That makes sense:

P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)

DTC P0421 Warm-up catalyst system efficiency below threshold DETECTION CONDITION

• PCM compares the number of HO2S (front) and HO2S (rear) inversions for a predetermined time. PCM
monitors the number of inversions the rear side performs while the front side inverts for a specified number
of times when the following monitoring conditions are met. PCM detects the inversion ratio. If inversion
ratio is below threshold, PCM determines that catalyst system has deteriorated.
MONITORING CONDITIONS
— Engine speed is 1,500—3,000 rpm.
— Calculated load is 15—48%(*1).
— Vehicle speed is 28—120 km/h {17.3—74.5 mph}.
*1: Maximum calculated load value varies depending on engine speed.
Diagnostic support note
• This is an intermittent monitor. (CATALYST)
• MIL illuminates if PCM detects the above malfunction conditions in two consecutive drive cycles.
• DIAGNOSTIC MONITORING TEST RESULTS is available.
• PENDING CODE is stored if PCM detects the above malfunction condition during first drive cycle.
• FREEZE FRAME DATA is available.
• DTC is stored in PCM memory.
Diagnostic procedure 01–02B

POSSIBLE CAUSE
• WU-TWC deterioration or malfunction
• Exhaust gas leakage
• Looseness of HO2S (front)
• Looseness of HO2S (rear)
• HO2S (front) malfunction

STEP INSPECTION ACTION

1 VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
Yes Go to next step.
No Record FREEZE FRAME DATA on repair order, then go to
next step.

2 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Check for related Service Bulletins availability.
• Is any related repair information available?
Yes Perform repair or diagnosis according to available repair
information.
• If vehicle is not repaired, go to next step.
No Go to next step.

3 VERIFY RELATED PENDING CODE OR
STORED DTCS
• Turn ignition key to OFF then start engine.
• Verify related pending code or stored DTCs.
• Are other DTCs present?
Yes Go to appropriate DTC troubleshooting.
No Go to next step.

4 INSPECT EXHAUST SYSTEM GAS LEAKAGE
• Visually inspect exhaust gas leakage in
exhaust system.
• Is there any gas leakage?
Yes Repair or replace faulty exhaust parts, then go to Step 7.
No Go to next step.

5 INSPECT INSTALLATION OF FRONT AND
REAR OXYGEN SENSORS
• Inspect for looseness of front and rear oxygen
sensors.
• Is it okay?
Yes Go to next step.
No Retighten sensor, then go to Step 7.

6 INSPECT WU-TWC
• Clear DTC using WDS or equivalent.
• Inspect WU-TWC.
(See 01–16–19 WARM UP THREE-WAY
CATALYTIC CONVERTER (WU-TWC)
INSPECTION.)
• Is WU-TWC okay?
Yes Replace suspected oxygen sensor, then go to next step.
No Replace WU-TWC, then go to next step.

7 VERIFY TROUBLESHOOTING OF DTC P0421 COMPLETED
• Make sure to reconnect all disconnected
connectors.
• Turn ignition key to ON (Engine OFF).
• Clear DTC from memory using WDS or
equivalent.
• Start engine and perform OBD-II DRIVE
MODE except for MODE 4.
(See 01–02B–10 OBD-II DRIVE MODE [FS].)
• Is PENDING CODE of same DTC present?
Yes Replace PCM, then go to next step.
No Go to next step.

8 VERIFY AFTER REPAIR PROCEDURE
• Perform “After Repair Procedure”.
(See 01–02B–9 AFTER REPAIR
PROCEDURE [FS].)
• Is there any DTC present?
Yes Go to applicable DTC inspection.
(See 01–02B–15 DTC TABLE [FS].)
No Troubleshooting completed.

Thanks guys (2thumbs)(2thumbs)

So my shop said they put new plugs and an O2 sensor in and it runs like a champ. I suspect this is not it, but hey... We will see!!!

^yeah a bad o2 sensor won't cause the flashing light and random misfires directly...it'll push the ecu code 'too long for closed loop', or something like that...along with a few others...which will remain until the sensor is swapped, but allows the car to be driven (albeit, off of a 'limp' map, giving noticeably bad gas mileage)...

p0300...the random misfire code...can be caused by several things...if its flashing, and the car is obviously missing...its almost always one or both coils, multiple plugs/wires, or a direct problem with the fuel system pressure (failing pump, ruined injectors, etc.)...while the car isn't usable during the problem, its at least easy to find the source...

but, if the car hesitates for a second..then returns to normal...and the engine light remains solid after that...its harder to track down, as something screwed up but then returned to normal...that can be a o2 sensor, egr valve, vacuum leak (has its own codes too, though), evap system malfunction, etc...or even just a gulp of crappy gasoline...

so just be glad your's blinked and it seems to be fixed...its a lot easier to diagnos a problem that keeps repeating...than these phantom issues that misfire once, then are fine for weeks...

Sounds an awful lot like an EGR valve popping open and not shutting. Very common. Has yours been replaced/cleaned lately or replaced with the Canadian version? I used to be cruising down the highway ~50 mph - MIL would start to flash, poor throttle repsonse, no power...sometimes snapping the throttle would clear it, sometimes I'd have to pull the valve and clean it. It would throw a P0300 random misfire(hence the flashing MIL), and sometimes a P0401 EGR fault.. If you can get to a point where you can drive the vehicle a certain way and consistantly duplicate the issue, try unpluggin the EGR valve electrically and seeing if the symptom goes away. While upgrading the EGR to Canadian is the best option, you may buy some time by cleaning it. The P0300 is not normally caused by secondary ignition components (plugs/coils). Rather, if you have a fault with a plug or coil, the PCM is pretty good at setting a cylinder specific (p0301-304) code, and thats even the case with injectors on indiviuals cylinders as well. An O2 sensor will never cause the MIL to flash or set a misfire code unless mabye you try and splice the wiring of the O2 and coils together.....

tweety2300 said:

Or in the short basic layman a terms, when your car misfires it doesn't burn the fuel, that fuel gets into the precat which destroys it.

If this happens you will get p0421. A new one from Mazda is $1,000. But if you don't have super strict emissions you can deal with it for $10 with a non fouler and get a rotten egg smell every once in a while, or get an aftermarket header to delete it with the non fouler. You won't get a cel and will still pass the sniffer test but if they check to make sure the Pre cat is there you will fail. But with just the non fouler they won't know the difference

Click to expand...

^This. The ignition coils go bad and take the cat with 'em. I recommend the non-fouler trick 1,000%

OK... back in town.. picked up the trusty P5 Auto from a reputable shop. New Timing Belt, new water pump, tensioner, etc. He said it had a bad coil and the plugs were the wrong heat range. Starts and runs great, and as I was driving away from the shop, dipping into about 1/2 throttle... that wheezing/buzzing/whine/whistle sound was there. Just like when it was starting to lose power on the interstate and check engine flash last week. Anyway, I drove it a little, got it hot, ran on the interstate, etc. I noticed when I got on the back roads to come home, it seemed to have a little more power and the 1/2 throttle and above whistle/buzz is gone.... Is there some sort of air door or hot air diverter that could be choking out my intake and what I hear is air whistling by the air door or something? Runs great, but that mid to full throttle whistle/screech is strange. Do the lifters and followers get adjusted on a timing belt change? Perhaps I hear a little tic that wasnt there in the followers, or perhaps now I am gunshy and noticing every little sound now.. hahah Thanks folks for any ideas on that sound...

Megazuel said:

Sounds an awful lot like an EGR valve popping open and not shutting. Very common. Has yours been replaced/cleaned lately or replaced with the Canadian version? I used to be cruising down the highway ~50 mph - MIL would start to flash, poor throttle repsonse, no power...sometimes snapping the throttle would clear it, sometimes I'd have to pull the valve and clean it. It would throw a P0300 random misfire(hence the flashing MIL), and sometimes a P0401 EGR fault.. If you can get to a point where you can drive the vehicle a certain way and consistantly duplicate the issue, try unpluggin the EGR valve electrically and seeing if the symptom goes away. While upgrading the EGR to Canadian is the best option, you may buy some time by cleaning it. The P0300 is not normally caused by secondary ignition components (plugs/coils). Rather, if you have a fault with a plug or coil, the PCM is pretty good at setting a cylinder specific (p0301-304) code, and thats even the case with injectors on indiviuals cylinders as well. An O2 sensor will never cause the MIL to flash or set a misfire code unless mabye you try and splice the wiring of the O2 and coils together.....

Click to expand...

Hi there.. I did not notice there was a page 2. How big of a chore is it to pull the EGR? I have NOT done it, but I hear it needs to be cleaned and they clog on these little cars... I am mechanically inclined and have worked on cars all my life. But it's funny how the older I get and the busier I am, I fond myself doing less and less.