Lately at a few stoplights and stop signs my car has been studdering from 500 rpm's to 1000 rpm's and it will die. It just started to do this yesterday and has been doing it for two days now. I'm not to sure what it could be. My mods are in sig. I don't know if my plug wires are arching? My opti is about a year old, since then for some reason i have gone through litterally 4-5 water pumps, since they all leak out of the weep hole after a week or so. Does anyone have an idea what my car is up to??

Zach

 

first thing that comes to mind is checking the IAC

 

How would i test this? I'm more of a carburator guy.

Zach

 

Where are you buying your water pumps from? That's ridiculous.

 

Clean out the IAC at the mouth of the TB with carb cleaner.

I don't think it would be your wires unless you got them wet. How old are your plugs?

Driven through any puddles lately?

Does your car run rich at all at idle? Black smoke out the back?

Leaky water pumps and the surge at idle would make me suspect the opti is toast if the car is running rich.

Get an electric WP next time.

 

Plugs are a year old. It has been raining a lot lately. I hope my opti is not toast, its about a year old, but i have had alot of wp trouble, and I dont know why. Grip, it only does it less than half the time. IAC how do i clean this, where is it on the TB.

Zach

 

Hope this helps (from www.shbox.com)



Good luck man.

-J

 

Does it miss anywhere else in the rpm band?

Any black smoke when this is happening?

 

I just got back from lunch and drove it about 10 miles, stop and go, no problems. It runs really well everywhere else in the powerband. It has a little bit of black smoke at WOT, that is about it. What would i use to clean the IAC? I am stumped, sometimes it runs well, and other times it runs like garbage at idle. Idle is where the problem is, nowhere else.

Zach

 

I actually used carb cleaner on my IAC.

-J

 

What does this IAC function as? Like I said before my car runs great most of the time, other times it runs like garbage. I wonder if cleaning this IAC out will do anything, It probably has 200,000 miles on it.

Zach

 

IAC is the black thing in the above picture. It opens and closes a pintle which limits how much air is going into the engine. If the computer wants the car to idle higher, the needle will open up more to let more air in.

The injectors know how much fuel to deliver because when more air is let in by the IAC, the more air there is passing through the maf sensor.

I cleaned my Throttle body yesterday actually. If you don't have the TB coolant bypass done, it's a little messy because the coolant lines still go through the throttle body.

You may need a new throttle body gasket, and you may want to do the coolant bypass while your in there Its also best to do this on a cool engine, as the parts will be hot if you just drove it making it a bit tricky

#1. Remove the cover on the acellerator cable. Disconnect accellerator cable from the TB.
#2. Remove the 4 bolts from the TB.
#3. Carefully remove the sensors and vaccume lines connected to the TB.
#4. You may now need to remove the coolant lines if !TB Bypass was never done. Search for a guide on that.
#5. Dissassembly the throttle body completly and clean all components and passages. When cleaning the IAC valve, be careful not to push on the needle much as it can wreck it.
#6. Reassemble everything back.