Help - Rough Idle and CEL

[protpibe]

Here's my problem:

My car is running very rough right now, the idle dips below 500rpm and it surges back up to 800-1000 just before it stalls. It started doing this when the temperature started getting a bit colder (winter, go figure). It originally only did it when the car was almost fully warmed up, but now it does it all the time. The car has not stalled, but the CEL just came on yesterday.

I have an 03 Protege5, 5 speed with 46,000km on it. It has a Shortram intake, and catback exhaust. I doubt it's relevant but I changed my plugs to bosch platinums about 4000km ago, and I do regular oil changes to Mobil1 Full synthentic every 6k.

Has anyone else had this problem, and if so, whats the fix? I want to make sure the few mods I've done aren't the problem so that I can bring it in for warranty.

Thanks,
Alex.

[ELEmental59437]

Take the car to autozone if you are near one or some other place that will scan the CEL code and tell you exactly what its coming from. It could be the plugs, intake installed wrong, or that your ECU wasn't reset properly. Did you gap the plugs properly?

[protpibe]

The intake and exhaust has been on the car since it had 500km on the odometer, so they've been there for almost 2 years now. The plugs have been installed since summertime, so I don't know how they would just start causing a problem now. They were gapped properly when installed.

I'm just going to take it to mazda and see what they say.

[leeit2me]

I would bet it's the EGR valve stuck open. This is a common problem with protege. Take it out and see if it's stuck open. Then try to move the plunger up and down with a screw driver, it should feel smooth but if it feels rough. You need a new egr valve which runs about 150 at the "stealer".... dealer I mean.




The intake and exhaust has been on the car since it had 500km on the odometer, so they've been there for almost 2 years now. The plugs have been installed since summertime, so I don't know how they would just start causing a problem now. They were gapped properly when installed.

I'm just going to take it to mazda and see what they say.

[crazybassmp5]

I had a problem with Cel P0340 and 505ZOOM erased it from the computer for me, and hasn't come on since. I think the Cel was for some camshaft sensor error, but your problems sound like what I had, rough idle and just driving like crap. Haven't taken to dealer yet though, but it's been about 3K miles so far with no other issue yet.

[meinp5]

I had a problem similar to this. Take a look at the top of your throttle body and see if the little vaccume line has came off. If you want to know what it looks like you can check out my cardomain web page. There is a little selenoid that came off the stock airbox that has two vaccume lines and one of those goes to the throttle body and if that has came off then your idle will be all screwed up and your CEL will come on. Thats what happened to me and it was a simple enough fix.

[jeffmp5]

I had exact problem, and as many suggested, it was EGR valve.
Since your car is still under warranty, it's NO COST to you.
Just take it to the dealership and mention the EGR valve since it's a known problem on proteges.
(but had wait a while since it was on back order! High demand, indeed)

[Protege52003]

your dealer will clean it out for you and then have you wait till they get one in. i had mine done a month ago. the cleaning lasted for the month or so i had to wait for one to come in......

[Kooldino]

I'm having this exact problem right now. P0340, stalling, stumbling, going rich at low rpm if I let off the gas too fast. But I have my EGR plugged...

[Dimitrios]

So, replacing an EGR with another Mazda unit will solve what? I've had the same issues for about 8k miles but never really considered that a TSB would be out there for it.

I don't think I've ever had to replace an EGR in any of my cars...ever.

I'd rather replace it with an aftermarket than have Mazda replace it in kind with another faulty unit.

[Kooldino]

Why exactly does the EGR fault cause this problem, btw?

[protegerider18]

I heard Protege's have problems with the EGR valves too but why doesn't Mazda recall it then?

[zmanpro63]

I have a 99 ES with almost 60,000 miles on it, AWR header, 2.25" SS custom header back exhaust, and an AEM SRI, I have noticed for awhile now that at idle when the car is warm the RPMs will dip suddenly almost like it is going to stall then they catch up, the CEL is on but that may be the header (Im still dealing with that issue, gonna check the code today) does the RPM dip sound like an EGR issue?

[ChopstickHero]

EGR problem. If you're under warranty, you can get it fixed no problem.

[zmanpro63]

Ok question 2, Im not under warranty, does anyone know of an online source for EGR valves at a good price? Ive seen 199.00 but Im hoping for less. If anyone is interested I have a great source for O2 sensors great prices front and rear O2 sensors OEM and universal. Thanks Nik

[zmanpro63]

Ok I found an EGR valve for the 99 - 03 Pro both the 1.8 and 2.0 engines for 142.97. Does this sound like a pretty good price? The site is Mazda Parts Cheap.

[Dimitrios]

I'd contact Richard in Austin, TX at www.mazdastuff.com

[zmanpro63]

Thanks Im doing that now.

[Kooldino]

Did it fix your problem?

[Micah]

Here's my problem:

My car is running very rough right now, the idle dips below 500rpm and it surges back up to 800-1000 just before it stalls. It started doing this when the temperature started getting a bit colder (winter, go figure). It originally only did it when the car was almost fully warmed up, but now it does it all the time. The car has not stalled, but the CEL just came on yesterday.

I have an 03 Protege5, 5 speed with 46,000km on it. It has a Shortram intake, and catback exhaust. I doubt it's relevant but I changed my plugs to bosch platinums about 4000km ago, and I do regular oil changes to Mobil1 Full synthentic every 6k.

Has anyone else had this problem, and if so, whats the fix? I want to make sure the few mods I've done aren't the problem so that I can bring it in for warranty.

Thanks,
Alex.
Plugs might play a part, but if the gap is the same as stock - then I doubt it.

Changing your oil every 6k though, that's kind of a stretch. I use full synthetic and change it every 3k usually, although I stretched it to 5k twice when I just didn't have the time.

The point of using synthetic is that the molecules are more uniform and thus take longer to break down and begin clumping into odd sized molecules that increase friction as compared to fresh oil. By doubling the length of oil changes, I'm sure you feel the difference in your wallet (most morons love to say this : "it costs twice as much, it should last twice as long") but you really aren't doing the engine much of a favor by using synthetic for extended periods. You'd likely see the same results using a partial synthetic for the regular 3,000 mile interval.

Oh, of course you could always go the Amway/Quixtar/Confederated Products route and use AMSOIL. It's a full synthetic oil, but I personally won't touch the stuff due to the over-zealous MLM people peddling it.

[Micah]

I have a 99 ES with almost 60,000 miles on it, AWR header, 2.25" SS custom header back exhaust, and an AEM SRI, I have noticed for awhile now that at idle when the car is warm the RPMs will dip suddenly almost like it is going to stall then they catch up, the CEL is on but that may be the header (Im still dealing with that issue, gonna check the code today) does the RPM dip sound like an EGR issue?
FWIW - after I blew my engine and put in the new one, I had a problem where the engine would every once in a while (maybe once a week) do exactly what you mentioned above. I'd be sitting at a light, suddenly the RPM's would drop for a second below standard idle, and the engine would kinda burp back to the proper idle (never stalled, but there were times when I thought it might) and then the CEL light would come on. I'd drive and a day or two later - the light would turn off.

The code I was getting was something like "Bank One Lean" or something. Eventually I found out that I hadn't plugged the wiring harness into the EGR. Turns out it works better plugged in. Plugged it in, never saw a problem since. No CEL, no dropped RPM's. Car runs perfect. Damn thing was covered in snow this morning, I woke up, looked out the window - used the remote start (I left the defroster on the night before) - hopped in the shower. By the time I made it to the car, no snow - warm car.