hello and thank you for responding. i recently checked it out and found out it idled bad because the throttle was set too low on the throttle body. it idled at 500 rpm. i raised it to 750 and now my issue is fixed. thanks for the advice though
Hi,
No problem! If you run into other problems, just wanted you to know this. Is the throttle body stock, and is the Cam stock?
This idle getting lower just occurred out of the blue-correct, If true, that indicates another issue caused the low idle.
As a general rule of thumb, when a low idle condition occurs, you do not adjust the throttle body when you want to set your idle, it’s done electronically.
The CPU is responsible for maintaining your idle speed via IAC & TPS in varying circumstances.
For instance, if you were to get your CPU reflashed after you installed a radical cam & built the top end of the motor, the idle speed would be raised within the new ECU program to offset it to a new parameter.
If you move the TB set screw in or out, the base idle will change. However, the car may try to compensate and run the car at the preset computer setting. If the base idle is on the low side, for example, the idle will tend to "hunt". It will jump around trying to find the correct sweet spot.
An example of a low base idle setting causes a rough or jumpy idle. A high base idle setting will certainly result in a higher idle...but not generally how it’s done. With new components some tweaking along with tuning is done, not for an issue that just “occurred” with no changes made.
The TPS would first needs to be set correctly. The TPS is nothing but a variable resistor, like a volume knob in an older radio.
Adjusting the TPS.
1) Turn car to key on, engine off.
2) Turn on your multimeter on and set to DC Volts.
3) “Tap” the green wire on the TPS with the red wire of the DVOM.
4) Place the black wire of the DVOM on a good grounded source on the engine.
5) Loosen the retaining screws on the throttle position sensor.
6) Twist the TPS sensor clockwise or counter-clockwise to make adjustments.
7) You want voltage to be below 1 Volt: between .75 and .98 is acceptable.
8) Tighten retaining screws on TPS & recheck the voltage.
If you do run into problems, post it & and we’ll work towards repairing it
Take care!
-John