Well, I have a mild street port, DP, intake. That's it for performance mods. At operating temp, my car idles at about 1000-1100 idle. I know this can be because of a vacuum leak, but I have new silicone hoses (of course one could have popped off) I am going to check the voltage of the TPS to make sure it is correct. I do have a tiny quiet bit of backfire poofs I can hear out the muffler as well. I went ahead and adjusted the idle screw to lower it to about 800-900, but under that, it seems like it is stumbling and shaking...any thoughts?

Trev

 

How long as it been doing it? Did these symptoms start after to vacuum hose job?

 

that idle is fine with a streetport. In fact, thats probably why it stumbled when you turned it down. With the porting it needs a bit higher idle than normal.

 

THanks FOR THE TIP. It has been like this for the previous owner for years I found out...he had the motor rebuilt in 02 or 03. I will look up the reciept.

Trev

 

TPS could be out if you possibly moved it at any given time, but I wouldn't think it would be your problem.
Try making sure your fast idle cam is releasing after warm-up, and that the throttle stops are touching the adjustment screws. Although the FSM says little on setup, I have been told that the throttle screws should just be touching when the throttle valves are all the way closed, and not hanging the valves upen.
Turn your air adjustment srew all the way in and then back it out two turns.
Warm up the car and jumper GRND and TEN on your diagnostic connector. The idle should go up a little.
Turn in and out the adjuster screw until you get around 850 or so and then remove the jumper.
You also want to make sure your Dashpot isn't hanging the throttle valves open.

 

My streetport idles smooth at 750 RPM. I find that AFR's richer than about 11.4 make mine backfire a bit.

 

1100 RPMs for a street port is rediculous. You have a vacuum leak somewhere, or you need to check your idle adjustment screws.

Either way, there is no reason that your car needs to idle that high, or should idle that high. I have a medium street port and I idle perfect at 800 RPMs

 

This is EXACTLY was Rotary Reliability and Racing told me today. They said that the mild port will do nothing for raising the idle. Boost seems to be coming on strong and I have a full silicone hose job, so I am not sure about the vac leak being the issue. I am going to check the TPS, but I will do the diagnostic test as well...

Now, there are 2 air idle ajdustment screws...the one on the side of the TB towards the front of the car and there is one on the firewall side, correct? Which is the one I adjust?

Trev

 

Two? No, there is only one and it is on the bottom of the throttle body.

 

Yes there are two idle adjustment screws. One under the throttle body, and the other is near the front of the throttle body when facing the front of the car.

 

Check if the ingoing and the out going coolant pipes to the choke and not clogged. Mind had this effect on my ideling puls other that got worst unitl I got the casue.

 

You said two "air" idle adjustment screws.