I have a 2006 hyundai Azera with about 100,000 miles. Sometimes I'm driving and the check engine light starts blinking and when I pull over I notice shaking by my feet. The shaking seems to get better when switched into park. (This has happened twice, both times at 50+ mph) After I turn the car off and let it sit for a few minutes, I turn it on and it drives normally. The engine light goes off in a day or two. I have been avoiding highways because of worry it will happen again. My mechanic says it may be the vct valve? But can't make a diagnosis without it acting up in front of them. What could this be??

SOURCE: Check Engine light flashing

Pull the code(s) at the moment the Check Engine light is flashing. Purchase an OBDII scanner (Auto Zone, Car Quest, O'Riely's, etc.) Be ready when it happens... do not shut off the engine ... plug the OBDII scanned into the DLC (Data Link Connector) and retrieve the code(s) at the moment it happens. If you still don't retrieve any codes when this happens, you have a malfunctioning ECM (Engine Control Module). Before you replace it (if this actually happens - no codes and Check Engine light is flashing), Disconnect both battery cables and touch them together for 30 seconds. Reconnect them to the battery and drive vehicle to see if it happens again (could be junk/corruption in ECM memory banks). If it happens again, the ECM is malfunctioning. REASONING: Whenever the "Check Engine" light comes on, there is ALWAYS a DTC (Diagnostic Trouble Code) stored in the ECM (Engine Control Module). If no codes are retrieved, there's only one cause - ECM MALFUNCTION!

SOURCE: 99 hyundai accent starts sometimes. not battery

ok when the check engine light comes on that usually indicates a engine malfunction...what you can do is go to your local autozone and they can do an OBDII test for free..my bet says it is the cam or crank sensor.. DO NOT SHUT THE CAR OFF AT AUTOZONE..LOL

SOURCE: 2004 Sonata stalls out for no reason then won't start

hi there, i have a 2003 sonata and my car did the same. it stalled and the engine light stayed on but managed to get going again. i took it to Hyundai and it was the crank angle sensor. it needed replacing at NZD180.00 with 3 hours labour to do it. evidently they remove the front of the engine and cam belt etc. the workshop at Hyundai did it and charged 3 hours, not sure if that was excessive or not.

SOURCE: Check Engine light and ESC OFF light

I had an issue where the ABS and ESC lights would go on and wouldn't turn off unless I restarted the car (sometimes they would light up again even if I had restarted). This was because the speed sensor was broken on my back tire. After the dealership replaced it, (under the 36,000 mile warranty) all was good and I have yet to see the lights come back on.

Summary:
Issue: ABS & ESC would not turn off
Solution: Replaced broken speed sensor on tire

SOURCE: 2001 Elantra stall, loss of power. Driving at

I am having the exact same problem with my 2001 Hyundai Elantra. I was told that the engine code that comes up when the sensor is on is called "Absolute Pressure In The Manifold". I was told by a "Hyundai Specialist" that when that code comes up it usually means that the seal on the manifold is Fuct. When my mechanic checked that out for me he had noticed that my manifold had 4 cracks in it(can varify cause he showed me). He replaced the manifold and gasket. The car ran fine for about 2-3 days and since then the problem has since come back and my check engine light will no longer go on/off it only stays on. Because of the check engine light always staying on I have noticed that on many occasions my car will hiccup many times in a row. The only way to stop the hiccup I have noticed is to take my foot right of the gas for approx. 2-3 sec then car will continue without hiccup(till it happends all over again). All in all I have been having this problem now for approx. 1 year and if there is somehow someway it could be repaired I would appretiate it.