Q: Hot start issues

asked by on October 20, 2017

Car starts up fine when cold but when hot it’s cranks for awhile then starts rough new spark plugs ignition switch and starter u don’t what else to test what should I do next

My car has 131000 miles.
My car has an automatic transmission.

The air fuel ratio is off on your hot starts probably due to sensors or controls operating out of range or perhaps due to a stuck open EGR valve. Heat affects ignition coils and can also adversely affect sensors such as the crankshaft position sensor and so those are two additional ignition system related possibilities. What a mechanic would do is methodically test all those components which potentially affect the air/fuel ratio such as the idle air control valve, coolant temperature sensor, injector operation, crank sensor output and so forth. Of course, the ignition system has to be considered as well (even with the correct air fuel ratio, you still need ignition). If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a hard starting diagnostic and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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