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Belisarius
08-24-2008, 04:01 PM
I have a 5 speed '95 SC with a SCP intake kit, Kooks mid length headers, SCP down tubes and cats and a 2.5" true dual mandrel bent exhaust.

The idle in this car holds at 1,500 rpm if you rev and lift off the gas. The car, after 15 seconds or so (sometimes longer), will gradually drop, usually in stages, to a 700-800 rpm idle. Is there some easy bypass or fix to actually cut the fuel with the throttle is closed so the idle drops quickly. I'm used to manual tranny cars that drop to idle immediately upon releasing the throttle.

I can't remember where but I recall reading something about computer controlled idle having something to do with improved emissions.

Thanks for putting up with a question that's already been asked.

David

rickbtbird
08-24-2008, 04:16 PM
What was done to the car prior to this idle issue? Was the IAC or throttle body removed or parts replaced?

Before you troubleshoot any idle issues find and eliminate any vacuum leaks before you do anything. Also, do not clean the throttle body or put any solvent through it.

On throttle body’s that have the adjustments, adjust the idle as outlined below.
STEP 1
Activate engine running Self-Test.

STEP 2
After diagnostic trouble code 11 or 111 has been displayed, unlatch and within 4 seconds latch the STI button.

STEP 3
A single pulse code indicates the entry mode, then observe the Self-Test Output (STO) of the STAR tester in Step 4. If adjustment is required in Step 4, ensure all other causes have been addressed and corrected before continuing.

STEP 4
A constant tone, solid light or "STO LO" readout means base idle rpm is within range. To exit test, unlatch STI button, then wait 4 seconds for reinitialization (after 10 minutes it will exit by itself).
Beeping tone, flashing light, or "STO LO" readout at (8 Hz) indicates Throttle Position (TP) sensor is out of range due to over adjustment; adjustment may be required.
Beeping tone, flashing light, or "STO LO" readout at (4 Hz) indicates base idle rpm is too fast, adjustment is required, go to Step 6.
Beeping tone, flashing light, or "STO LO" readout at (1 Hz) indicates base idle is too low, adjustment is required, go to Step 5.

STEP 5
Do not clean the throttle body turn the air trim screw counterclockwise until conditions in Step 4a are satisfied. Process completed.

STEP 6
Do not clean the throttle body, turn the air trim screw clockwise until conditions in Step 4a are satisfied.