Fast Idle and RPM climb
 

Hello people, this is my first forum experience. Also my 98 SS 6speed is my first real performance car. I bought it last summer. In 2006 the car had $10k of engine work done (including the labor cost). Cam, rocker arms, lifters, tuned on a Dyno etc. I have all the paperwork. Only 4k miles since then. It sat for the previous four years because in would not pass my area emission test. I put Knock sensors under intake and it passes. My V8's from past all had 4bbl carbs. I knew how to adjust them. This being a tuned fuel injected delivery it idles TOO high, in my option.

First question, Does 1100 idle seem high? I found a small set screw under throttle stop. But, any backing off of it causes stalling, Not at idle but when RPM drop from revving or even shifting as you drive.

Second question, Why does any shifting over 2500 RPM has a momentary increase of RPM? It is annoying as all heck. I have a G6 GTP 6speed as my daily as well as the majority of my life driven a stick, the Camaro makes it sound like I don't know how to drive a stick. I went over every square inch of the cabling even under the dash. Its all free.

Any input would be appreciated.

I assume this car has always done this. When you change a cam you are changing the design of the engine. You can compensate for some of the changes with tuning but not all of it. The bigger the cam the worst the idle. As the CAM gets bigger the low RPM torque curve starts to disappear. AKA stalls. I have worked on race engines that would not idle under 1800 RPMS. This is worse with a stick, you have no torque converter and you need torque to get the car moving.

There could be something wrong with the car or it could just be the way it is. Only a skilled tuner is going to be able to help. That is the price of having a aftermarket cam.

Thanks Gorn, I thought i would post it first. I am heading out to the place that built and tuned it on Monday. Maybe revisiting the tune may help. Even though it was ten years ago.

Good idea, I am sure in the last ten years tuners have learned more and there is more aftermarket support for sensors.

I had the high idle problem, made me crazy. would idle fine at startup then climb to 1200, sometimes 2000, even 3000. Turned out to be the throttle position sensor on the side of the MAF. $35 & easy swap out, end of problems, idles at 700. FIXED!

Enjoyed this thread,I've had a bit of high idle with mine sometimes and now I know what to check.
I have a pretty lumpy cam in my LS1 with LS6 heads,long tube headers no cats and a tune, 1100 is about where it will stay running without lobing out.