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HOMESERVICE MANUALSCHEVROLET1987STEP VAN P20, 7.4 W, AUTOMATIC, 400/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 4 (ENGINE CONTROLS - SPECIFICATIONS - GASOLINE)FUEL SYSTEMIDLE SPEED & MIXTURE
1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40

Idle Speed & Mixture

1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40SECTION Idle Speed & Mixture
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Idle mixture on fuel injected models is controlled by Electronic Control Module (ECM) and is not adjustable. Controlled idle speed and IAC count can be checked using scan tester. See CONTROLLED IDLE SPEED & IAC COUNT table.
CONTROLLED IDLE SPEED & IAC COUNT

Application Idle RPM (1) IAC Counts
4.3L TBI
"C" & "K" Series
Auto. Trans. (2)(4) 537 5-30
Auto. Trans. (2)(4) 650 20-35
Man. Trans. (3) 550 2-20
5.0L TBI
"C" & "K" Series
Auto. Trans. (2) 500 5-30
Man. Trans. (3) 600 5-30
5.7L TBI
"C" & "K" Series
Under 8500 GVW
Auto. Trans. (2) 550 5-30
Man. Trans. (3) 660 5-30
Over 8500 GVW
Auto. Trans. (2) 550 5-30
Man. Trans. (3) 600 5-30
7.4L TBI
"G" & "P" Series
Auto. Trans. (2) 750 5-30
Man. Trans. (3) 800 5-30
(1) Add 2 counts for engines with less than 500 miles. On 4.3L and V8 engines, add 2 counts for every 1000 ft. above sea level.
(2) Automatic transmission in Drive.
(3) Manual transmission in Neutral. Tech 1 scan tester will display "RDL" with transmission in Neutral.
(4) Calibration identification is not given by manufacturer. IAC count and actual RPM should correspond to one of these calibrations.
RENDER: 1.0x

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