Hey guys, I'm trying to figure out how to fix my rough idle and surging trouble. I had a question though, when you disconnect the IAC, should the engine's idle change? Or should anything happen at all? Because when I disconnect mine, there is to change to the engine at all.

Oh, also, I don't know if this could be related or not. But I also have a ticking coming from what I believe is right around my drivers side exhaust manifold. It is there when it's cold and warming up. But once it's fully warmed up, it for the most part goes away. I was thinking exhaust leak where the manifold meets up with the head, but I'm not sure. Also have about a 2 1/2" in diameter hole in my muffler that probably isn't helping matters either.

 

the ticking is probably a loose bolt or a very small crack on the exhaust manifold. this can cause a drivability problem that will make the engine run rich as the o2 sensor "sees" extra oxygen, and adds fuel to compensate for what it thinks is a lean run problem

how many miles on your engine? has the problem gotten gradually worse, or bad all of a sudden?

as for the idle not changing when the iac is unplugged, more than likely a dead iac. or your throttle blades were adjusted open too far by a previous owner to aid a failing iac. at any rate you can re baseline the car by doing the following in this order :

check ignition timing and set to 0*(for now)

shut engine off, jump terminals a and b in the diagnostic port for about 20 seconds with the key on, then go unplug the iac. this SHOULD seat the iac fully.

*important* remove jumper from diagnostic terminal

reset the base idle with the throttle screw and shut engine down. replug iac and go drive for about a 1/2 hour so that it can "relearn".

 

Ok, I don't think it's an exhaust leak anymore. It's starting to not make the noise so much since I did the oil change, so I put some of the lifter quieter stuff in there to see if it makes a difference, and it's MUCH better now. Can't hear it at all. The only thing that's stumping me is the idle issue.
Oh, the car has 160k miles on it, I just bought it last week.


Oh yeah, I checked the spray pattern for my injectors too.. They look pretty good, it's nice and misty coming out in the form of a cone.

 

Ok, I just put in a new IAC valve and adjusted it according to the Haynes manual. Still, when I unplug the valve while the engine is running, I get no change at all. Also, when I unplug my TPS with the engine running, there's no difference then either. Does anyone know if it's supposed to be this way? All my other cars when I'd unplug those connectors, it had an obvious change in the way the car ran.