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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Gasoline >> Trouble Code Charts >> Code 35, Idle Speed Error 2.5L & 4.3L Turbo >> System Too Lean
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System Too Lean

If air/fuel ratio is too lean, the idle speed may be either too high (check for vacuum leaks) or too low. Engine speed may vary and disconnecting the IAC may not help. Scan and/or digital voltmeter (10 megohm) will read an oxygen sensor output less than 300 mv (.3 volt). Check for low fuel pressure or water in the fuel.