Increased Accelerator Pedal Effort (Replace Throttle Body). GMC Truck GMC C Sierra

Subject:

Increased Accelerator Pedal Effort (Replace Throttle Body)

Models:

1999-2000 Chevrolet and GMC C/K Pickup Models (Silverado and Sierra)

with 4.8 L, 5.3 L or 6.0 L V8 Engine (VINs V, T, U -- RPOs LR4, LM7, LQ4)

This bulletin is being revised to include instructions on reading the Date Code, and added text on which Throttle Body Assemblies to replace. Please discard Corporate Bulletin Number 00-06-04-007A (Section 04 -- Engine Controls).

Condition

Some customers may comment on a higher than expected accelerator pedal effort from the idle position.

Cause

Condition may be caused by a tight throttle blade in the throttle body bore when in the closed position.

Correction

Notice: DO NOT adjust the shipping air screw to rotate the throttle body blade away from the throttle body bore. Adjusting the shipping air screw compromises the idle speed control, and may lead to other driveability concerns. Adjusting the shipping air screw may lead to reduced Idle Air Control valve durability.

Verify the cause for this condition is not a damaged or binding throttle cable.

Figure 1 - Throttle Body Date Code Identification


(1)	Location of last 5 digits of Throttle Body Assembly Part Number
(2)	Location of 4 digit Julian Date Code
(3)	Throttle Body Assembly

Remove the throttle body (3) from the engine and inspect the 4 digit Julian date code (2) stamped on the bottom edge of the mounting flange.

The Julian date code is stamped on the lower edge of the mounting flange, next to the gasket edge, on the side of the throttle position sensor. The stamped 5 digit code (1) is the last 5 digits of the Throttle Body Assembly Part Number. See Figure 1 - Throttle Body Date Code Identification.

If the Date Code is 2979 , or earlier (Indicating the Throttle Body was built before the 297th day of 1999):

•	DO NOT clean the Throttle Body Assembly.

•	Replace the Throttle Body Assembly using the Service Manual procedure.

•	DO NOT attempt to adjust Throttle Body Assemblies.

Notice: All 1999 models whose Throttle Body has not been replaced will have a date code prior to 2979 and should be replaced for this condition.

Reading The Date Code

The four digit Date Code can be interpreted as follows:

Example -- Date Code 2979

The first 3 digits (297) represent the calendar Julian date.

297 = the 297th day of the calendar year.

The last digit (9) represents the last digit of the year.

•	8 = the year 1998

•	9 = the year 1999

•	0 = the year 2000

•	1 = the year 2001

Parts Information

Model Year	Part Number	Description
1999	17113597	Throttle Body, 4.8 L V8 w/Manual Transmission
1999	17113583	Throttle Body, 4.8 L and 5.3 L V8 w/Automatic Transmission
1999	17113558	Throttle Body, 6.0 L V8 w/Automatic Transmission
1999	17113599	Throttle Body, 6.0 L V8 w/Manual Transmission
2000	17113639	Throttle Body, 4.8 L V8 w/Manual Transmission
2000	17113665	Throttle Body, 4.8 L and 5.3 L V8 w/Automatic Transmission and w/o Traction Control
2000	17113640	Throttle Body, 6.0 L V8 w/Manual Transmission
2000	17113652	Throttle Body, 6.0 L V8 w/Automatic Transmission and w/o Traction Control
1999, 2000	17113561	Seal, Throttle body (not shown)

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation	Description	Labor Time
J5485	Throttle Body - R&R	Use Published Labor Time
J5490	Throttle Body Replace	Use Published Labor Time