First off, I changed the oil and my "uncle buck" smoking problem is almost nill. But I have noticed that every time I start the car the rpm's rocket to 3k for about 30 seconds but after that it idles around 1- 1.2k, if I take it for a drive I find myself feathering the gas while trying to hold the brake just to keep the motor running. Any ideas? Is this a sign of a larger problem or something easily solved? thanks in advance.

The starting up and rocketing to 3k for 30 seconds is part of the accelerated warm up process. That's normal. It should be idling around 800-900 though, not 1200.



Feathering the gas while holding the brake to keep it running...why?



What weight oil are you using?

20w 50, If I don't feather the throttle it stalls every time I come to a stop. Kind of annoying when waiting for the gate to open at my complex. And at stop signs, lights, etc,etc.....

does it have auto or manual tranny?

hmm could be a vacume leak

As Quack said when you start it and it revs to 3k it is part of the accelerated warm up process. Try starting the car in gear and it shouldn't rev so high. While cold it should idle around ~1,200rpms to warm the engine up. After the engine is warm it should idle around ~750 which is the stock idle.



While the engine is warm and you are sitting still what do the rpm's do when you apply the brake? What about when you turn on the rear defrost or turn on the headlights? It could be a faulty BAC that isn't responding to the new load on the engine from the electrical system.



All of this is IIRC of course. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Have you set your TPS yet?

Manual trans

WTF is a BAC?

Haven't touched the TPS, Didn't know there was an issue with it.



Thanks guys for helping.

I have the same problem with mine. I got it 2 weeks ago the guy thought it was the apex but was the Crank angle sensor. And my BAC is new

Ok did a search on BAC and am wondering how do you test it? and what does it look like? Furthermore, if it's bad how do I delete it?

Bypass Air Control or some crap like that. Let's see...



http://www.teamfc3s.org/main/factory_servi..._SYSTEMS_NA.pdf



Page 4A--62 and 4A--63 should tell you how to test the BAC and where it is on your car. Personally I would keep it. Isn't hurtin' anything and keeps your car from idleing like ****. Mine is bad and I hate not having it... Waiting on a used one to come in actually...





TPS is very easy to check. If, you have a multimeter or DVOM or somehin' like that. Ooooo... Actually I don't remember if checking it is the same on S4's as on S5's. I know how to check it on S5's at least. https://www.nopistons.com/forums/pub...R#>/unsure.png



Someone else is going to have to pick it up from here I think. I didn't work on my S4 very much at all...

my mother has the same problem when she drives my car... its cause she forgets to push in the clutch when stopping. No wonder my clutch is **** and slipping like hell.



The first thing that popped into my head was the bac, but if it happens all the time, then thats prob not alternator-load related unless u have a system in your car and are always playing it, or forgot to shut the AC off or something.



Id try just adjusting the idle screw right on top of the intake manifold. Its covered in a little black rubber cap. When the car is warmed up and idling, loosen that screw a little bit (1-2 turns or so)and see if the engine changes pitch or seems to idle a bit stronger.

I'll check the BAC sometime this weekend, if I can break free from the wifes plans. Anyhow I stopped by a local salvage yard today and sitting in the corner was a near perfect 87gxl. They wont sell me the entire car, but told me to make a list of what I wanted from it and he'd make me a deal. I figure I'm gonna take everything but the chassis. What I am wondering is, the five lug conversion is basically remove and replace right? And what is involved in switching to power windows from manual, is the wiring already there? Just plug in a fuse and call it done?



I'll be selling everything I'm not gonna use from this car for whatever I have into it. not looking to make $ just sharing the wealth.

When ever you do sell your stuff, I would love those manual windows and door panels.

They're yours. I spoke with the guy yesterday and he told me. $800 he'll deliver the whole car, and after I'm done he come and pick up whats left. So needless to say he'll only be gettin the unibody back. Anyone in south florida wanna help strip it?