Rough Idle when stopped...

S

sting

Member
Hi all,

I have a 2002 Protege LX2.0.

Recently I've noticed that when I stop at a light, the idle will jump around from 500, then up to 800, then to 700, then to 500, then to 700, etc, etc. Really unstable.

And now in the last day it seems to be taking an extra second or two to start the engine.

Other than that it runs perfectly fine... when driving the engine is great.

I've checked the battery and it's fine. No warning lights have ever come on.

What could this be and what tests can I do???

Lance
 
Has you car been worked on recently or had the battery unhooked for any reason?
 
Mine was doing the same thing, I have a 2002 P5. It did it for a couple of days, then the engine light came on, I took it to the dealer yesterday, they replaced the egr valve and gave me the old one. 360 bucks total (drunk) they said it was probalbly due to the removal of the cats. I am thinking of putting my stock header back on now.
 
gone_fishin said:
Save the $360 and DIY. It's extremely easy and should take no more than an hour.
Click to expand...

I would have, if could have found this topic sooner. The dealer wanted 106 just to find out what was wrong with it, I didnt find the part any cheaper than 175, so I was allready at 295 or so with tax to do it myself. As you can see I just paid them an extra 60 bucks for them to do it, and now I have an extra one. I will clean that one out, so next time it happens I will just do a swap.
 
ENTENSE said:
Mine was doing the same thing, I have a 2002 P5. It did it for a couple of days, then the engine light came on, I took it to the dealer yesterday, they replaced the egr valve and gave me the old one. 360 bucks total (drunk) they said it was probalbly due to the removal of the cats. I am thinking of putting my stock header back on now.
Click to expand...

(wow) you can clean it yourself...also, don't forget to clean the IAC (idle air control) while you're at it
 
ENTENSE said:
I would have, if could have found this topic sooner. The dealer wanted 106 just to find out what was wrong with it, I didnt find the part any cheaper than 175, so I was allready at 295 or so with tax to do it myself. As you can see I just paid them an extra 60 bucks for them to do it, and now I have an extra one. I will clean that one out, so next time it happens I will just do a swap.
Click to expand...

Sorry you didn't find the topic before you shelled out the cash! We could have saved you quite a bit. Unless it's waranteed, always DIY. If you can't DIY, take it to a reputable mom & pop shop. Avoid the dealership like the plague.
 
sting said:
Hi all,

I have a 2002 Protege LX2.0.

Recently I've noticed that when I stop at a light, the idle will jump around from 500, then up to 800, then to 700, then to 500, then to 700, etc, etc. Really unstable.

And now in the last day it seems to be taking an extra second or two to start the engine.

Other than that it runs perfectly fine... when driving the engine is great.

I've checked the battery and it's fine. No warning lights have ever come on.

What could this be and what tests can I do???

Lance
Click to expand...

Lance, I forgot to add that there's a chance (although it's very small in comparison to the dirty EGR, or the IAC), that you have a leaking intake manifold gasket. You can check that by taking carb cleaner and spraying it around where the IM meets the head. If you hear the engine rev slightly, you've found a leak.
 
my idle has been a little rough lately, too. I ran a 1/2 can of seafoam thru my intake manifold yesterday and it idles like brand new now. I've cleaned my egr before, its really easy and helps a bit if your egr is in fact clogged, but I highly recommend tyring out the seafoam. Its ~$7 a can and takes 10 minutes to do.
 
sam1 said:
my idle has been a little rough lately, too. I ran a 1/2 can of seafoam thru my intake manifold yesterday and it idles like brand new now. I've cleaned my egr before, its really easy and helps a bit if your egr is in fact clogged, but I highly recommend tyring out the seafoam. Its ~$7 a can and takes 10 minutes to do.
Click to expand...

Through the PCV?
 
ENTENSE said:
Mine was doing the same thing, I have a 2002 P5. It did it for a couple of days, then the engine light came on, I took it to the dealer yesterday, they replaced the egr valve and gave me the old one. 360 bucks total (drunk) they said it was probalbly due to the removal of the cats. I am thinking of putting my stock header back on now.
Click to expand...

No. That didn't cause it (ignore them! Clowns!) The cats are downstream of the EGR system and our car runs very rich at WOT by design (not becasue the mods to the exhaust).
 
I have a problem with my cars check engin light also. My mechanic has run the code and tells me that the reason its on is because I took the cat out. I have tsudo header and the light has been on ever since installed. IS there anything I can do?
 
spark plug non-fowler trick. I believe there is a writeup in the how-to forum.

edit in: Since I'm nice, I even found this thread for you. There are 2 ways, resistors or non-fowlers. This thread goes over both of them, but I recommend the non-fowler since there is no cutting of any wires.

http://www.msprotege.com/forum/showthread.php?t=52498

And this thread has alot of info on the non-fowler trick, without having to read thru all the resistor crap on the prvious thread I posted

http://www.msprotege.com/forum/showthread.php?t=66426&highlight=sensor+exhaust+bung
 
Last edited:
Use the non-fouler trick, it's easy. All you need is a 1.2" drill bit. Just don't drill into the concrete in your garage like my friend and I did installing mine.
 
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