rough idle problem...thats what she said?? :)

[cole naymark]

Hello everyone!

I'm having a rough idle problem with my 99' 1.8L mazda protege. I'm pretty good with mechanical stuff, so feel free to be technical...here's the history up till now:

I bought this car 2 years ago, it ran fine and things were peachy. Last year it started having rough idle issues. It would dip down from 900 rpm to about 200 rpm and jump back up, sometimes it will do that 3 times in a row, sometimes only once, but only at stops. There are no on road issues with the car. I have read around and thought it was possible to be the EGR valve. I took it off today, cleaned it, lubed the shaft of it, and put it back on the car. Still have the same problem.

I ordered the shop manual today hoping to trouble shoot some voltage readings from the either the mass air flow sensor or the o2 sensors.

I checked the intake boot, no tears or leaks there.

I'm thinking that the EGR may still be the problem, I don't know if a cleaning is really all that needs to be done or not? maybe replaced? also, can I just throw it away and plate over the opening? or will that leave me with the nasty orange glow of the check engine light for the rest of my life?

Any tips would be more then appreciated! thanks a ton!!!

Cole

[KZL_99ES]

mmm, did you have the shop plug into the OBDII port? well i guess that would only say if you are throwing a code, is your cel on?

and for cleaning you egr, you actually have to clean the part that connects to the intake itself not just the tube...

it sounds like you could have a vac leak too...

[cole naymark]

mmm, did you have the shop plug into the OBDII port? well i guess that would only say if you are throwing a code, is your cel on?

and for cleaning you egr, you actually have to clean the part that connects to the intake itself not just the tube...

it sounds like you could have a vac leak too...

I was thinking a vac leak was probable... I haven't checked the code yet, it usually takes about 50 miles or so to come pop up. I checked it last time but I had an old intake boot that had a tear in it between the MAF and the throttle body. I haven't got a code since, but the idle is still bad. (I was hoping that vacuum leak was the problem, but it wasn't).

I suppose I could just stand around with some starting fluid and just spray it on the motor until I see a raise in RPMs?

Either that or wait for another code to pop up, or start pouring money into it...ahhhhhhhhhhhhhhhhhhhhhhhh

new egr valve?

[prof15]

It can also be a dirty or stuck egr valve.I was having rough idle a few month ago and after cleaning the MAF sensor, changing plugs, cables, coil packs and nothing.. the last thing I did was to clean the egr valve which seem to solve the problem. There is a how to in the forum if you want to try cleaning it.

But like KZL_99ES find out what codes are you getting since that will tell help you diagnose the problem.

[cole naymark]

It can also be a dirty or stuck egr valve.I was having rough idle a few month ago and after cleaning the MAF sensor, changing plugs, cables, coil packs and nothing.. the last thing I did was to clean the egr valve which seem to solve the problem. There is a how to in the forum if you want to try cleaning it.

But like KZL_99ES find out what codes are you getting since that will tell help you diagnose the problem.

I will wait for another code to get thrown and see what it says, I think I may buy a new egr, I already removed it and cleaned it but I couldn't remove a lot of the carbon buildup. The MAF looks great, but I will check its voltage with the manual I found online here. This is a great site, thanks so far for the info! I'll keep you guys updated towards the end of the coming week when I get some time to work on my car again!...this fucking weather makes riding the motorcycle to work a little hard, damn MN

[cole naymark]

well, the check engine light finally came back on...I'll go back to the auto store tomorrow to borrow their code reader...

Just an extra thought. What do you guys think would happen if I removed the EGR, plated it shut, and jumped the relay to make it think the egr was properly connected?

[cole naymark]

I replaced the EGR valve today and still no luck... The check engine light came back on though and read out "lean condition" which I am guessing has to do with the o2 sensors? Also, I tried spraying starter fluid all over the motor and didn't see any idle changes so i'm guessing less likely to be a vacuum leak?

so now i'm wondering if a bad o2 sensor could cause the idle to jump all over the place between 900 and 200 rpm?

Any help would be greatly appreciated, Thanks

Cole

[slowhonduh93]

im not sure if this will help but when this happened with my civic, the problem was the idle air control valve. Not really sure if your protege has one of those or not. Good luck though.

[KZL_99ES]

my rough idle is due to a not fully purged air from the coolant/radiator... could you have the same issue?

[cole naymark]

Protege's do have an IAC valve, so that could be an issue,

The second issue that was mentioned could be it too? i've never heard of the purged coolant thing though, how do you fix that?

[cole naymark]

fixed it, check here:

http://www.mazdas247.com/forum/showthread.php?t=123760714