I have noticed that about 10% of the time my Silverado has a hard time starting. When I turn the key, it starts cranking strong but it goes through a lot of cranks before it actually starts. It does not sound like a low battery in that it does not start cranking slowly and then speed up. I have replaced the thermostat due to a different issue but the cranking problem had started before the thermostat problem. This problem occurs on both a hot and cold engine. I heard it could be the mass air flow sensor and just wanted to get a second opinion. Thank you.
My car has 63000 miles.
My car has an automatic transmission.
Hi there. A malfunctioning mass air flow sensor may create the extended crank concern; however, a sticking idle air control valve can create the same concern. Cleaning of either components has been known to help with the situation. However, this is rarely a long term repair and is only temporary.
You could clean one at a time and see which one alleviates the extended crank and replace as necessary. Also, there may be a residual fuel pressure problem. Residual fuel pressure is the pressure that remains in the fuel lines and injectors to provide immediate start up fuel. If the check valve in the fuel system is bleeding off, this could definitely be the cause. However, since it is only 10% of the time, it may be difficult to verify.
I recommend having a certified technician, such as one from YourMechanic, assist you with an idle speed inspection to determine if a mass air flow sensor replacement or idle air control valve replacement may be necessary.