idling funny?

[DSMe36]

my car has been acting up recently.
well it idles like it has some aftermarket cams, sounds like a misfire maybe?
i replaced sparkplug, wires, and coilpack but still having the same issue.
at times its idles low like 500 at other times 1000. my car seems to run fine but at stops its gets all weird. please help.

 

[gusu]

Are you talking about idle surge?

If so here is a list of things it can be.

Bad ISC
Bad caps on your ECU caused by a bad ISC
You need to clean your throttle body
EGR failure
It could also be from your battery or alternator not giving enough power to the electrical system in your car. However this would be very obvious since your lights would dim A LOT when you come to a stop not just a bit because the car does generate less charge while not moving.

To fix your problem I'd start off with the simple steps.

Check your ECU since it takes the least amount of time its right under your head unit. Look for any signs of leaking caps.

Next step is spend that hard earned 20 dollars for a EGR block off plate and a EGR gasket... I know 20 bucks is horrible. Pull off all the BS emissions hoses and cap them off for maybe another 1.20 or something I don't know it might be less. It will make your engine bay look cleaner plus with your EGR blocked off you have less carbon build up in your intake since the hot unburned gas is no longer being cycled back through.

How to check if your ISC stuck is covered on VFAQ and so is the EGR. Check there.

The alternator is fairly easy to test. If you know how to test it then do it yourself if not try to find someone who can. Same goes for the battery.

Well, I think that just about covers it.

 

[DSMe36]

hey thanks for all that info. i'll try all that today.

***my car isn't the 420a anymore btw*** its the 4g63

 

[DSMe36]

yeah that idle problem ended up that my car was off timing, and it jumped like 4 tooth.
but i fixed it already, took it to a machine shop, my valve seats were bad so they did that,
and i replaced all gaskets and belts. now my car runs better than ever

 

[Ghost1984]

Good to hear you got your idle problem figured out! It's too bad it was something that extreme instead of a bad ISC or something simple.