Accord 3.0L
- Disconnect vacuum hose located between top of throttle body and intake air by-pass control valve at control valve. See Fig 1. Connect vacuum pump/gauge to open end of hose. Start engine and run at 3000 RPM under no load with transaxle in Park or Neutral, until radiator fan comes on. Allow engine to idle. Vacuum gauge should not indicate any vacuum. If vacuum gauge does not indicate any vacuum, go to next step. If vacuum gauge indicates vacuum, check throttle cable adjustment and go to next step.
- Open throttle slightly from idle and check vacuum gauge reading. Vacuum should exist. If vacuum exists, go to next step. If vacuum does not exist, check throttle body port for clogging. Clean as necessary and go to next step.
- Turn engine off. Check throttle cable operation for binding or sticking. If cable operation is okay, go to next step. If cable binds or sticks, check cable routing. Reroute or replace cable as necessary and go to next step.
- Operate throttle lever by hand to see if throttle valve and/or shaft are too tight or too loose. Replace throttle body as necessary. If throttle valve and shaft are okay, go to next step.
- Check for clearance between throttle stop screw and throttle lever with throttle lever fully closed. If any clearance exists, replace throttle body. DO NOT adjust throttle stop screw.
Courtesy of AMERICAN HONDA MOTOR CO., INC.