I have a 2002 Hyundai Accent with a 1.5 L Engine. The engine will not hold it's idle speed, it surges up and down.

SOURCE: timing belt on my 2002 hyundai accent 1.6 liter 4cyl

DID THE BELT BREAK AND THEN IT WAS CHANGED. If so then you may have bent valve. IF NOT then vehicle may be timed wrong. Here is a diagram of your timing marks, http://www.2carpros.com/car_repair_information/tec_info/2002/hyundai/accent/2002_hyundai_accent_timing_belt_diagram_marks.htm contact if you need more help. Thanks for using FIX YA

SOURCE: rough idle / engine surges until power is applied

Sounds like a possible vaccume hose leak?

SOURCE: check engine light flashing

light will flash when accellerating,if this is the case ,it s misfirering, car must stumble,check scan code,spark plug wires coil pack,

Marvin

• 85242 Answers
• Posted on May 04, 2009

SOURCE: at idle engine surge's up and down usually a few hundred RPM's

DS THIS PROCEDURE
Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Delage guy

• 167 Answers
• Posted on Apr 29, 2010

SOURCE: 1998 camry 5sfe engine, surging at idle

Check for air leaks in the vacuum pipes in and around the inlet manifold, they have a habit if going brittle and splitting.
Another possibility is the temp sender , if the ecu thinks the engine is too cold it will compensate causing the engine to " hunt". This can be something as simple as a worn radiator cap seal letting air into the cooling system and tricking the sensor.
Hope this helps, Marshall