What is the correct RPM's for idle?

bassjas12

Member
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2003 Mazdaspeed Protege #704
When I start my car in the morning the RPM's will stay just under 2k and then slowly start to fall. Eventually as I drive they will get down to about 750 and then stay there. Occasionally It will bog down a bit to the sub-500 range, but then comes right back to around 750.

Just wondering if this is normal, or if not, what is? And, If it is not Normal, what I should look for to try to get it to where is should be?

Know its prob a noob question.... but i am what i am. (uhm)

Thanks for any help.
 
I idle at 800-900 but I tuned it to that idle..... I think that is the same as a stock MSP.

Rob
 
I idle at around 750 too and that idle dip could be a few things. A lot of the time it is a dirty EGR valve which can be fixed with a couple of hours and some carb cleaner or something. There is a how-to in Stealthwyvern's quick links.

Do you have a boost gauge? When my WGA went out I got the idle dip really bad. I cleaned the EGR and it kept dipping. I replaced the leaky stock WGA and everything is just fine now. That idle dip is something that all of us have had at one point or another haha. Luckily it is usually no big deal.
 
Ive removed the EGR and sprayed it out really well with carb cleaner. Just kept doing it until there was no dirty liquid coming out anymore.

Today I blew into the vac tube running to the Wastegate and it did not let any of my air go through. So i do not think there is a leak there. I was blowing really hard and still got nothing.

I do not have a boost guage yet. plan on getting one eventually. Just too broke at the moment.
 
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Yea definitely get a boost gauge. It could be a bad vac line. How do you have your lines ran? When I installed a vac block on the brake booster and ran my vac lines differently, it definitely helped a lot with my dipping idle.
 
plugs and wires are new. I have heard lots of people talk about seafoam on these forums, but never used it before. Do you add it to your gas?

Where is the PCV located at, and what do i need to look for?
 
i idle at at 700-800 normally, but mine will sometimes dip too. Doesnt sound like you have any big problems to worry about, def check vac
 
plugs and wires are new. I have heard lots of people talk about seafoam on these forums, but never used it before. Do you add it to your gas?

Where is the PCV located at, and what do i need to look for?

I tried to find a pic that I posted to show but the search function is not the best. Its underneath your engine cover sitting in a grommet on the cylinder head cover. A Purolator PV1047 is the one that I use.

You can use seafoam in the gas tank, in the crankcase and to decarbon the engine using a vacuum source. I always use the PCV hose. Pour it in slowly using a funnel stuck in the hose while goosing the throttle with my right hand while its going in. Let is sit for several minutes and then start the engine and go for a drive after letting it idle for few minutes. I usually put the rest of the can in the tank with the next fill up. I've used it a often over the years.

1001220zu6.jpg
 
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Thanks for the info, Will have to give the seafoam a try out, and see if I can get it to resolve any issues with the idle.
 
Replace your PCV also, the one in your engine could be clogged or leaking. For $3 get a new one and put it in.
 
Just got home from work. Think I will go and see if I can figure out what the PCV is, also making a belt adjustment.

Update: Think I found the PCV, did not look to be leaking. Snapped a Photo, to make sure I was looking at the right think. I was able to pull up on it, and It just came out. Dunno if that's normal.

PCV.webp
 
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