Have 2002 Sonata, the car starts fine and then die when the engine is warm (approximately after 10 minutes of engine runnning). After that, it will not start. It doesn't start also in the morning, it will just crank but will not start. Have check all fuses and all are okey. Spark plug is new, oil at required level and water in the radiator is full. Please provide possible problem and solution.

Perform tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-11.html#post2123675

Perform tests in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-11.html#post2123675
Thanks for the help, your link is very informative. Just a follow-up to my question, what are the symptoms of fuel system problems. My car normally starts when the engine is normally cold (not too cold - does not start either) but dies when reaches the normal temperature. My mechanic friend told me it might be the fuel pump or the ckp.

Forget about it being the fuel pump--they are extremely reliable and not the cause of engines dying when they heat up. The Crankshaft Position Sensor (CKP) is a real possibility and easy to replace.

Forget about it being the fuel pump--they are extremely reliable and not the cause of engines dying when they heat up. The Crankshaft Position Sensor (CKP) is a real possibility and easy to replace.
Thank you TxGreaseMonkey. I already replaced the CKP, Timing Belts and Tensioners and the car starts fine and didn't die anymore. Two more problems I need to solve, maybe you can help. How can I smoothen the idle of my car, the RPM needle is intermittenly moving between 900 to 1000. I need to lower the RPM and make the needle steady at the required RPM range. Further, can you please tell me the color code and position of the wires in the Vehicle Speed Sensor. My car's VSS is not working since I bought the car. I check the VSS and I found out that it was broken and the connector is missing. There are three loose wires near the VSS and I believe these are the wires to the VSS without the connector. Thanks in advance.

. Clean/replace the Idle Air Control Valve (IACV).

. Clean throttle plate and throttle body.

. Clean upper and lower ports.

. Clean air box and replace air filter.

. Set idle rpm to specification (likely 700), when engine is at normal operating temperature.

It sounds like you are on the right track with the VSS. Get a Haynes Manual to help you identify what wire goes where. Sorry I can't be of greater service.

. Clean/replace the Idle Air Control Valve (IACV).

. Clean throttle plate and throttle body.

. Clean upper and lower ports.

. Clean air box and replace air filter.

. Set idle rpm to specification (likely 700), when engine is at normal operating temperature.

It sounds like you are on the right track with the VSS. Get a Haynes Manual to help you identify what wire goes where. Sorry I can't be of greater service.

Thanks for your prompt reply. How to adjust the idle speed on 2002 Sonata 2.4L DOHC. I don't see any distributor on the engine. Does the ECU automatically control the idling speed base on the sensors input or it can be adjusted manually. I want to lower my RPM to standard specification.

See if you can make the adjustment at the throttle cable.