Wont Idle Well

[shaneyeend]

It is the weirdest thing, it randomly desides it doesn't want to idel, it wont ever die but it will go from its normal 900rpm down to maybe 100 and then jump up to 1500 then settle to 900 for maybe a second then drop again, I thought it was a tps so i replaced it and still had the problem.

 

[Locke]

I would start with basic tune up items and go from there.

Read the plugs, 2 steps colder may not get hot enough to self clean during short or non spirited driving.

Check the wires, and check the resistance through the coils.

May try cleaning your IAC as well.

How's your air:fuel when this happens? Do you still have your EGR hooked up?

 

[Defiant]

Missing BISS O-ring.

Also, your spell checker is screwed-up.

 

[shaneyeend]

BISS O ring? No i don;t have an EGR anymore. My a/f jumps around when its drops.

 

[Locke]

We don't have a BISS on our engines.

You could try hooking the EGR back up, see if that helps/fixes the problem. And reading the plugs.

 

[shaneyeend]

Whats IAC stand for? I know my wires and coil are good, i checked those, but the plugs deffinatly could be a problem. problably should run atleast only one range colder when i'm not using nitruse. Wondering if 15psi would be ok with normal plugs. I'm not thinking it would be my egr, i've had it gone for like 3 years now, and it started acting up after i rebuilt the whole car, so i'm more thinkin something new is messed up.

 

[BigRand]

IAC = Idle Air Controller
~See Chiltons/Haynes manual for location

Also what is your fuel setup looking like. if you are runnign big injectors, it gets complicated on controlling the idle.....check your fuel pressure and make sure its high enough at idle, and you might want to have someone in the driver seat and see what the fuel pressure is like when the idle keeps going up and down.


Last thing to check is the vacum, espcially around the PcV valve area, you want to make sure that is working correctly and not broken...etc.

 

[Shadow98]

You could try cleaning or replacing your IAC. I had 2 go out on me within 1 year.

 

[VelocitàPaola]

Not an appropriate topic for Engine Management section...

 

[danny7481]

how do you guys clean the IAC? im having the same problem.
i blew the IAC with compressed air, didnt do anything though.
i would have cleaned the TPS, but the screws are stripped and i cannot remove it.

 

[shaneyeend]

my fuel set up is Hana Portfuler with factory injectors for mains. my fuel pressur at normal idle is 43. The idle is very random as far as when it wants to start jumoing around, 80% of the time it runs right.

 

[4UH8ERS]

I'M sure your check engine light stays on all the time as most peoples do with a 2gnt . So you probably wouldn't know if the engine was throwing a new code. Go have it scanned at auto zone and tell us what it says. With your setup and the time you have had it I'm going to bet your o2 sensor is about to take a dump on you. They usually are very random. Otherwise, it could definately be an IAC or the TPS like previously mentioned.

 

[BigRand]

Hey paul, you don't by chance have a good diagram to show the IAC, TPS, and such do ya? Just for calification for the origianl poster. I couldn't find a good enough picture in chiltions to scan in.

 

[VelocitàPaola]

I think I have one in the FSM. I'll post it later tonight.