Ok first off I wanna say thanx to everyone. Now as for this idle problem I had it even before the swap so I know its not directly related.

When I started the car up it ran perfect it makes more of a wwhistle noise under the hood but I think thats normal if not let me know.

I know all the vaccum lines are fine cause it didn't rev right high.

The problem it has and that it had before is that when I rev it a bit and it comes back down to idle sometimes its a little rough and sometimes it will dip low in the RPM range. I dunno if its my o2 sensor cause I remember reading that that would throw a code.

Any other guesses?

Don't know if it's similar to what you have but I had a rough idle problem and I changed the fuel filter.. idle was fine after that.




15.69@86.670 - stock 99Z

Ive changed that once already. Maybe I'll do it again just to be sure. Anything else?

usually the idle dip is cause from the IAC in some way

wether the iac is weak , partially clogged passage , to much dirt on the iac slowing it down

or a pcm issue

check the IAC, also what grade of gas are you using, I hope it's premium, my Quad stumbles a little with cheap gas.

check for leaks and make sure that IAC is good. I cleaned mine up. put it back together before I finished the swap. I'm glad I did. usually it has something to to with a leak somewhere. Try listening for something akward. it should sound like a normal engine with no hissing noise.

Whistle you say? It should not be making that nose... that means it must be some sort of leak or something. try looking around and seeing if your gaskets are good and everything is bolted on nice and tight.

make sure the TB is closed all the way, it will sound almost like a turbo at just the right position. it should be giving you a higher idle for that situation though, unless the IAC is correcting it.

it should sound like a turbo? how do you clean the IAC is there acertain way or jsut wipe if off kinda thing? I do hear a slight whistle but like I said it runs fine except for the idle jump which it already had before and the gaskets and what not seem to be pretty damn tight

I thought once you did this swap the engine would sound a little different

you have to remove the IAC, it's mounted in the throttle body.

If you hold the throttle at a proper amount, the air will rush past the plate and make a hissing noise similar to the noise a turbo makes. I've fooled a few people while sitting in a parking lot. give it just enough of a pedal press and it starts to hiss, and watch a couple heads turn.

so take the iac out and let it idle and it will rev higher if there is a vaccum leak>?

No, take the IAC out, and clean it, test it (per the service manual or Haynes), and put it back in. DONT MOVE IT!!!! As in, the pointy part that goes inside the TB, you could damage the servo motor. the car will idle crazy for a minute after you re install it, IF you happen to move it a little. It can move some, but dont yank on it or slam it all the way in.

If you try to run with out the IAC in the TB, the car will have a MASSIVE vaccum leak, due to the gaping hole in the throttle body.

hope that helps some, now, go get a Haynes manual at the local autoparts store. you will get more info there.

K I got the manual I'm gonna clean it all up today and test it out.

I cleaned the sensor up today and then ran the code reader and the only code i got was
P0405 which I am pretty sure is the erg code. The car still idles a little rough. As for using the ohmeter to test it I broke mine so didn't get to do that today try it tomorrow. Any other suggestions?

It says with the scan tool to go into a different monitor mode but I dunno how to do that kinda thing with the tool I just hooked it up and it had the emmisions code pop up.

EGR?!?!? nope, no EGR on a Quad. Did you swap the ECM? the 2.4L ecm will have troubles looking for an EGR. Also, if the ECM isn't changed, it will have trouble timing the motor correctly, and setting the idle. One final thing, if you dont change the ECM, you will lose a nice little extra, such as a 7200rpm redline. there's more, but I hope you changed the ECM

I did a manifold swap I have the 2.4 L twin cam. Your confusin me right now man

CzapskiKandyKav wrote:I did a manifold swap I have the 2.4 L twin cam. Your confusin me right now man

oh, ok then LOL nevermind

i have the EXACT same problem, it has a whistle at about 2500 RPM, at first start up it will hesitate when given throttle, has a freaky idle, bogs down. all the same stuff. I have a 2.4L no EGR but also the manifold swap, i chaged my IAC valve once cleaned TB three times still nothing, I have just bought a whole new ignition system basically, hoping to fix the problem since all the shops say "theres to much aftermarket on your engine" hopefully someone will come up with something.

damnit I want to go over to your house and fix this for you! ><

Is everything seated properly? is the TB on there right?

ya everything is the way it should be

you know whats wrong?

did you do the Relearn procedure? you know. key on, key off, key on etc?

you know what I didn't do that.

I just remembered something about that how did it go again

oh christ... I can't remember! give me a few minutes to look it up...

it is definantly the IAC valve, i messed with mine today and it got like 10X worse, ima work on it some my next day off.

its not throwin any codes to show and IAC failure though.