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Q: Truck runs rough in 80 to 90 degree weather

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my truck starts fine gos into a high idile they kicks down in to a normal one after that when it gets to temp and the themastat opens the gauge drops to where it runs and then it starts running rough when the weather is 70 to 90 degrees out you step down on it somtimes it gets a little better and somtines it dont hope you have a idea tried of throwing new parts at it

My car has 215000 miles.
My car has an automatic transmission.

With the age of your vehicle, there are likely a few things that need to be maintained. All of the recommendations about to be made depend on what other repairs have been made recently. Since the issues are related to the ambient air temperature, you will want to start by checking your cooling system. The water pump and thermostat are two critical components that do age and will need to be replaced eventually. To test the water pump: feel the upper radiator hose while running (carefully, it will be warm), if you feel a good amount of coolant inside then the pump is functioning well. If it feels empty or like there is bad circulation, you will want to replace the pump.

You will want to make sure your coolant is topped off and in good condition. Another easy step to take is to flush the radiator. You will have to remove it and use whatever means you have to flush clean water through it. There are some mild solvents that will help to clear any coolant buildup inside. If you would like an expert to take care of this, a qualified professional from YourMechanic can come to your car’s location to inspect the rough idle and pinpoint needed repairs.

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