Q: My car won't run when warmed up - 2008 Ford Mustang GT

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I have a 08 Mustang GT, when its cold no issue .as it warms up it wont take gas, and idles real choppy in the 300-500 rpm range, I get no codes on anything, I have replaced the fuel pump,strainer and filter, fuel presser sensor,cleaned the MAF, and T/B, replaced the throttle position sensor,throttle motor does work when its not running, I have tried the stock tune still no difference,plugs have been replaced 850 miles ago, Its not the gas filled other car at same place 1/2 after later and its fine

Hi there. It looks like you have inspected most of the common culprits of a choppy running engine. However, when the vehicle gets hot and has running issues, it’s commonly caused by the EGR valve or EGR valve temperature solenoid. As the engine gets warm, the exhaust gas recirculation valve can get stuck, leading to a lean engine condition, which typically lowers the RPMs as you’ve indicated.

Check this component and clean it and see if that clears up your problems. If not, I recommend having a certified mechanic, such as one from YourMechanic, come to your location to inspect your choppy engine issue and find the source of the problem.

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