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Q: Very hard to start vehicle

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would you have any insight on why it's very hard to turn on when engine is cold I live in Texas so it's not really cold .. It's gotten harder to turn on ? But once engine warms up it's finally turns on it runs smooth no hesitation or jerks . Only codes that came up are for the knock sensor and (2)catalytic converter below threshold efficiency . I put some cleaner in for the catalytic convertor and it took away one codes p0430 but the p0420 remains. New parts this month Fuel pump Fuel filter Fuel relay Fuel sending unit Water pump Timing belt Thermostat Harmonic balancer Throttle position sensor Temperature control sensor

My car has 222235 miles.
My car has an automatic transmission.

A: Hello. This code is also related to the cat...

Hello. This code is also related to the catalytic converter not working properly. This can also happen when the ground wires connected to the O2 sensors are not properly hooked up causing them to send erroneous info to the computer. Try checking these to be sure they are properly connected. If this does not solve it, try having the computer re-scanned. You have replaced many components already, so your best option may to have the problem diagnosed before changing any more parts that may not need replacement. If you need help with this, a certified professional from YourMechanic can come to your car's location to inspect the hard start and related codes in order to get this properly fixed.

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