Some 2004-07 Chevy Aveo models with 1.6-liter engines may produce an intermittent misfire that develops during deceleration or steady-throttle driving.
According to GM, the misfire typically occurs after a long period of inactivity (usually overnight), and may be accompanied by an illuminated check engine lamp with trouble codes P0300, P0700, P1781 and/or P0401 stored in PCM memory. Poor valve sealing is the most likely cause for the condition.
The fix depends on when the vehicle was built. On cars with a VIN breakpoint before 5B406012, replace the intake valves, exhaust valves and the valve stem seals with new-design components — part Nos. 96440081, 96830500 and 96840122, respectively.
On cars built after and including VIN breakpoint 5B406012, just replace the exhaust valves and valve stem seals.
"Factory Fixes" is written by Jim DePalma, a 30-year veteran of the auto repair business who has served stints as a service manager, parts manager and ASE-certified technician. His column provides vehicle manufacturers' authentic factory technical service bulletins (TSBs) that have been condensed for easier reading. Mr. DePalma advises that techs always check with a dealer or repair information system for the latest revisions before starting to work on a vehicle. He can be reached via e-mail at [email protected].