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Q: Loses power after engine get up to temp, runs good cold

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Truck runs great cold when it gets up to temp the power decreases greatly. new fuel pump, new fuel filter, new air filter has been hooked up to two different computers and it's showing no codes at all. New muffler and dual pipes,the old ones were bad. im at a loss and so are my mechanics

My car has 84000 miles.
My car has an automatic transmission.

A: Heat causes electrical resistance in a circ...

Heat causes electrical resistance in a circuit or component to increase. If you have a bad component that may have a bad internal connection, the increase in temperature could cause a voltage drop in the component. Also, heat can cause a crank position sensor to act up if it is starting to fail.

Temperature sensor failure can sometimes cause similar symptoms. The dashboard temp gauge typically uses a different sensor than the ECU uses to determine if the vehicle is cold or warm, affecting the amount of fuel that is required for proper operation. Ignition coils and also other components are vulnerable to higher than normal resistance from heat.

It may be tricky to try and diagnose this yourself, but a fun challenge for a seasoned, certified technician to figure out. In depth electrical testing of individual components will be needed to determine the exact cause of your vehicle’s loss of power.

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