Hyundai Repair: Idle Surging, hyundai lantra, actuator

Question
I own a Hyundai Lantra 1993 model that surges when idling until it warms up.  I have taken it to multiple mechanics and they all say they've fixed it but as soon as I get it home it does the same thing.  What could be the cause of this problem?

Answer
Usually, this occurs when too much air enters the engine for the computer to idle the engine at a low enough speed via the idle actuator.  It then begins shutting off injectors momentarily, causing the surging you describe.

Usually, this is caused by a misadjusted air bypass screw or a faulty idle actuator.

You need to take your car to a mechanic who's willing to look at the car, make repairs, and then keep it overnight and check it again to verify it's actually fixed.  Either the mechanics who've looked at the car haven't kept it long enough to verify it's repaired, or they just don't care.  The former is easily enough remedied by giving specific instructions to the mechanic to not return the car until it's verified that it's fixed.  The latter, on the other hand is fixable only by finding a mechanic that actually cares whether he fixes the problem.  You should probably start by speaking to the last mechanic to work on the car.  If reputable, he should be willing to look at the car again for no additional charge.  He should also be willing, on your request, to keep the car overnight after repairs to verify them.