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Q: Trying to shut off

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When I start up my truck it runs perfect. At and idle and while I'm driving it. When the truck gets up to temperature it tries to shut off and looses all spark on the drivers side. I shut it off for about 5 minutes start it back up and runs fine! I let it idle for 2.5/3 hours yesterday and it never tried to shut off. I just don't know what might be causing it.

My car has 191204 miles.
My car has an automatic transmission.

A: This is a common sign of a faulty ignition ...

This is a common sign of a faulty ignition coil. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle to properly diagnose your ignition system.

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