Mazdaspeed 2003.5 Under Idle Help

[MSP03BOI]

My Mazdaspeed 2003.5 orange protege is fine and it drives fine. It only under idles when i come to a stop or when i rip it and throw it into neutral. It under idles so far that its about to stall then it goes back to normal. Sometimes it goes so far that it feels like the car stalls and then turns back on. Otherwise its good. I was told by mazda it could be either my timing or my computer but i doubt it. Other people say it could be my egr but im not sure. If someone can help that would be great. Thanks alot

[1Mazda323Fan]

How many miles? Your timing belt could indeed be at fault. If it's close to the change interval, you might just want to go ahead and replace it. You might want to start with cleaning the EGR and PCV valves, as that's a wee bit easier and both can, and will, get clogged.

[Dragondima]

I have a Mazda Protege ES Sedan from 2002, and i have the exact same problem... well not exact but close. This occurs to me when i just start the car. In one case the car did actually stall. I definitely think this is a timing belt issue i'm going to get it checked out within a week or two and will definitely let you know what's said.

[mazdaman2002]

i know with some other vehicle's putting a full atmosphere bov can stall it out if you let off right after flogging it. as for the es the other suggegstions are good one's

[XelderX]

On the MSP...have you changed any of the intake, turbo, IC, or BOV piping to something aftermarket? I bet if you relocate you MAF to the boosted side of the intake piping it will stop doing that.

[MMProtege03]

dude i have the same car, except the orange MSP's are the 2003 not the 2003.5, but anyways, your problem is most likely the egr valve. i took mine off and soaked it in carb cleaner for like an hour and got all the gunk off of it. then the car idled like it should. just dont loose that gasket or it will idle like crap. the iac doesn't usually get dirty that much, well at least mine wasnt. the problem with the egr is that once it gets clogged enough it gets stuck open and is flooding the intake track with exhaust gas and is causing it to want to stall out. regular carb cleaner will work to get it back to normal. i usually clean it every 2k miles. also check all your vac lines for leaks. but believe me i had the exact same problem as you. so i hope you get it fixed.

[MMProtege03]

also to add to the other comments, i have my maf relocated and the car does move better, plus it allows you to blow off, but throttle response suffers because of all the boost that is lost. and if you are venting after the maf it will make is want to stall, but i dont know your setup.

[dtatham]

Clean your idle stabilizer valve. They build up gunk and stick. When you come to a stop it will practically stall, then it frees itself up then jumps to a high idle. You see much more fluctuation than you should. It could be the air filter, the egr or maf, but theyt will usually give you engine codes when there is a problem.

[MMProtege03]

o yea i forgot you can clean the maf too, just get some maf cleaner and spray the little wires in the center of the maf. (not the plug on the side). i mean on the interior of the maf in the intake tract.

[XxaltezzaxX]

i need to clean my EGR soon, maybe today.

[DeanSweetP5]

I say it's the EGR, My 2003.5 P5 had the same issue and soaking/cleaning it was highly suggested and once completed, the 'idle surging' went away. Takes maybe an hour to remove, soak and re-install?

[dtatham]

Easy way to clean EGR port

It's usually the port from the EGR to the manifold that gets clogged. It will give a P0402 error if it's stopped up. I found an easy way to clean it. Disconnect the rubber tube from the boost solenoid valve (that actually is used to isolate the pressure sensor for the manifold) and with the engine idling, draw seafoam or chemtool through the hose. Draw in a little, then pull the hose out or you'll cause the engine to stall out. Do this until about a third of the can is used. As far as the idle is concerned, unless the EGR is sticking opened, it shouldn't cause a problem. The idle stabilizer is usually the cause when I have surging and lack of tune up is usually the culprit with a rough idle.

The cleaning method I've given is for the port, cleaning a stuck EGR is described above by DeanSweetP5.