Rough Idle, Flashing CEL

M

Merrilin

Member
:
2003.5 Mazdaspeed Proteg
I turned my MSP on today to discover that it was idling very rough and uneven, and the check engine light is flashing. I'd just ordered and received my timing belt components in the mail and was going to replace the whole thing in a few days - I really hope my timing belt didn't fail just now. As far as I know that basically means I destroyed my engine. I'm at ~97k and it's never been replaced.

I used another car to get to work, but do you think that I could drive my MSP to the mechanic? I'm probably going to end up towing it with AAA. Any ideas as to what the problem could be?
 
Even if your timing belt went your engine would be fine. the FSDE is a non-interference engine.
 
Thanks for the tip. The plugs haven't been changed in a while - I in fact ordered new iridium ones when I ordered my timing belt. I'll change my plugs today or tomorrow and see what happens, although I don't see why my plugs would suddenly fail. Does this happen? Should I bother replacing my coils if the spark plug replacement fixes the problem?
 
Well when mine started to flash I changed the wires and plugs it still happened so I got coils and bam it was gone
 
Ignition coil most likely... one of mine failed around 85k.... change the plugs first and if it doesn't help then start by unplugging one of the coil packs while the car is running... that way you can tell which pack went bad ... if you unplug one of the coil packs and the car shuts off then that coil pack is still good., replug it and unplug the other coil pack (with the car running) if the car stays idling then you found the coil pack that crapped out
 
Merrilin said:
I don't see why my plugs would suddenly fail. Does this happen? Should I bother replacing my coils if the spark plug replacement fixes the problem?
Click to expand...

I had this same problem and replaced the plugs/coils. I found one plug had backed out and so it simply vibrated loose; must not have been torqued enoiugh from the factory. One plug would have fixed but i just went ahead w/ the full maintenence replacement. at least yours happened at home, not on the road!
 
protege3690 said:
Ignition coil most likely... one of mine failed around 85k.... change the plugs first and if it doesn't help then start by unplugging one of the coil packs while the car is running... that way you can tell which pack went bad ... if you unplug one of the coil packs and the car shuts off then that coil pack is still good., replug it and unplug the other coil pack (with the car running) if the car stays idling then you found the coil pack that crapped out
Click to expand...
I'm not an expert but that sounds extremely dangerous, considering the coil packs are delivering electricity on the scale of tens of thousands of volts.
chuck b said:
I had this same problem and replaced the plugs/coils. I found one plug had backed out and so it simply vibrated loose; must not have been torqued enoiugh from the factory. One plug would have fixed but i just went ahead w/ the full maintenence replacement. at least yours happened at home, not on the road!
Click to expand...
Thanks, I'll try replacing the plugs first. I think I can figure that out (I've never really maintenanced my car before) or get a friend to help. Also, I can't really afford to buy extra parts if I don't need them, although I'm willing to if it improves the overall life/performance of my car.
 
Take it to auto zone or whatever local auto parts store and have them plug the obd2 scanner to the car and see what codes pop up.
 
P0300 is the misfire code, and as the others stated it is almost guaranteed to be your coil packs. Mine crapped out this past winter with no warning and that is the code that I had. It may also throw a lean code. I was able to limp it home about 5 miles and changed them out.
 
When I use to own a p5 in the past,I had a misfire and it was the egr valve. Was a horrible misfire at idle. The car use to idle up and down ,etc
 
Yeah I just replaced one of my coil packs with a cheap autozone replacement and it now has a choppy rough idle. I'm going to order one online soon and replace it and return that one to autozone for a refund. Definitely sucks.
 
Rough idle is caused by plugs, wires, or coils.... As others have already stated numerous times that the coils are more then likely the issue. however beings that you have the plugs on hand replace those. if thats not it replace the coil packs... Ive had a rough idle issue a few times before and its always been plugs, wires, or coil pack.
 
So I got home from work and while preparing to replaced my spark plugs, I started my car to demonstrate to my friend what the problem was, and it appeared to idle just fine. Confused, I proceeded to install the spark plugs because they were due anyway. I used NGK (6441) ZFR6FIX-11 Iridium IX (one step colder).

When I was done I turned my car on and the idle was consistent and fantastic! My car was running better than ever. I went for the test drive, and when I got to the end of my street after a few minutes of driving, the very rough idle came back! It felt like 2-3 cylinders and like it was ready to stall. With no throttle it would idle at <100. This was quickly complimented by a horrible rotten egg smell that persisted until I got home. I did a little bit of research and I think that it may be my catalytic converter. A month or two ago my mechanic told me that I needed a new upstream O2 sensor. I'd bought a new one but didn't get around to replacing it.

My question: if my O2 sensor is causing me to run too rich and therefore saturating my catalytic converter, will replacing the O2 sensor fix it? Or will I have to replace my cat as well? Is there any way to clean it instead? I need the quickest/cheapest solution - my family is starting to get very annoyed that I have to borrow their cars for work.
 
evilmonkeyMSP said:
Even if your timing belt went your engine would be fine. the FSDE is a non-interference engine.
Click to expand...

Per AllData, Chilton, and MOTOR: The DOHC motor in the Protege (FSDE) is an interference engine. The DOHC in the Tribute is a free-wheeling design. The 2.0 SOHC early motors are free-wheeling.

I've never actually figured out who is right... I've always heard it wasn't, but all my technical data says otherwise. Either way, I've changed mine and advise others to do the same. I have very little faith in the dealerships service department to ask them, because here locally they'll hire just about anyone to write service. A perfect example- "They didn't make a Mazdaspeed until 06' and that was a 6." was a reply when I called to see what they charged for the R&R of the oil cooler gasket on my MSP.
 
protege3690 said:
Ignition coil most likely... one of mine failed around 85k.... change the plugs first and if it doesn't help then start by unplugging one of the coil packs while the car is running... that way you can tell which pack went bad ... if you unplug one of the coil packs and the car shuts off then that coil pack is still good., replug it and unplug the other coil pack (with the car running) if the car stays idling then you found the coil pack that crapped out
Click to expand...

dont do that, thats how u get shocked. unplug the injector. ull get the same results.
 
Merrllin in reference to your problem dont just replace o2 sensors. For one 90% of them are always good when people replace them. If you have any rich/lean codes popping up under o2 sensors its because the o2 detected it being lean. O2 isnt your problem there, vaccuum leaks, low fuel pressure, etc are what cause the condition and the code just pops up for the o2 seeing it. Your car isnt smoking is it? Mine had #1 cyl valve seals leaking oil into engine. It fouled my plugs and would chug like yours. Thats the only reason check engine light blinks is because of major misfires, your timing isnt an issue. Coils or plugs i'd check
 
Last edited:
Please log in or register to reply here.

Similar threads

F
2017 CX-5 Sluggish Engine Response After Belt Tensioner Replacement
Replies
6
Views
885
yrwei52
yrwei52
D
    • Like
Engine Knock/Rough Idle (2021 CX-5)
Replies
5
Views
4K
erhayes
E
I
Is it possible to check the Protege5 Timing belt?
Replies
5
Views
2K
pcb
P

Latest posts

Back