HoLLo

iTrader: (17)

I haven't found any sites that actual have documented LT1 stock idle. I can't seem to figure out why my idle has been at 1100 recently. Can't find any vaccuum leaks. Everything SEEMS ok. Is 1100 fine? I drove my old 95 3.4 the other day and its like around 600rpm..

Elliott's94Z

iTrader: (12)

Yeah thats a little on the high side. Mine starts off around 900 when cold and after warm up is lays at 650-700. Have you check your IAC or TPS counts?

CamaroRacing12

iTrader: (5)

thats extremley high..... u in park or drive? in drive it should be around 600 700

C Man

You can manually raise the idle by adjusting a screw on your throttle body.

What someone may have done is screwed it out far enough that even with the IAC closed completely, enough air is getting in to not allow it to drop below 1100rpm. Not sure what "work" was done before you bought the car... but I'd also check the throttle body to see if any extra holes were drilled, etc. as this would cause the same issue.

A vacuum leak not being calculated by the MAF will cause other issues as well at idle... especially one that is allowing that much air through.... so I'd really concentrate on checking the obvious first.

If you have a scanner... this will be a lot easier... all you'd have to do is read you IAC readings... and if completely closed... you'll be a little closer to the answer.

355z28

iTrader: (8)

the stock tachs off my guage reads 1000, but on my scan tool its only 800-850.

Bad_tx_Z28

iTrader: (3)

i had the same problem, i replaced my IAC and everything is good to go now

moserman

iTrader: (7)

i would just bend the tab back on the throttle body or else adjust the idler screw depending on which style you have.

C-MAN you have a badass car!

Formula350

iTrader: (3)

My tach is right on the nuts Mine says about 580-610, scanner says.... well 590-610 heh And since the tach doesn't have steps, I'm guessing at what the RPM is, then I look at the scanner and I'm nearly right on every time (even in the high Rs).

Anyways, does it drive fine, or stumble a bit? Or does it even idle rough? Might be the IAC like Bad mentioned.

sdm1234

iTrader: (8)

hmmm... mine idles around 1000-1100 too... i always just figured that was normal. great, that's another thing i have to look into haha

Formula350

iTrader: (3)

I don't know about PCM models, but my stock ECM bin shows

550 - +116c
550 - +104c
550 - +92c
550 - +80c
650 - +68c
750 - +56c
800 - +44c
800 - +32c
800 - +20c
800 - +08c
800 - -04c
800 - -16c
800 - -28c
800 - -40c

So basically, anything higher than 176F (80c) for coolant temp, you should be idling at 550-600rpm in drive and neutral. There are 2 columns but both have the same exact numbers.

HoLLo

iTrader: (17)

It drives fine. I feel this slight occasional .01 second stutter usually accelerating in 2nd or so, not sure if its related though.

Formula350

iTrader: (3)

Wouldn't hurt to replace the IAC, if you haven't. Or the PCVs while you're at it. They're all cheap.

Speed Density

iTrader: (38)

Im around 1300 on mine.

Adjust your Idle screw and check your IAC counts, those work well with each other.

wickedbusa

iTrader: (3)

Mine idles at 1200, but I'm heavily modded. I've noticed that M6 cars idle a bit higher than A4 cars.

Last time I had trouble with a high idle was with my old 94. It ended up being a bad plug wire. Have you checked your plug wires?

SS RRR

iTrader: (2)

TPS also needs to be checked. Scanning the PCM would be the easiest way or you can get a volt meter and test the voltage values open and closed. I believe shoebox's site can show you how. If not then a Haynes manual has the proceedure. I've always just taken the IAC out, sprayed a rag w/ brake cleaner and cleaned the IAC and the IAC bore out thoroughly.
The "idler" screw is not an "idler" screw. It is nothing more than a adjustable stop for the throttle blades to keep them from gouging the TB bores when they are shut. You want your blades adjusted so you can only see a hint of daylight through them. If you adjust the blades freely it can screw up the readings on a stock TPS.

chevyman_86

My car idles at 1500 rpm! I've checked for vacuum leaks the next step was check or replace the IAC as people mentioned above. I havent gotten to it but Im sure that will fix the problem and im sure thats probably whats wrong with yours.

HoLLo

iTrader: (17)

Hmm. My PCV valve was replaced not too long ago, but the elbow was rigged up with some tape, I can tell the PCV valve has a SLIGHT leak to it, but when I cover it up, I don't hear the idle drop. Does anyone know what the exact part number for a PCV valve elbow is? I can't find any that fit from the usual autoparts stores.

I'll replace the IAC probably within the month.