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Q: Why does my car stall when you press the gas and it tries to go faster than 20 mph? - 1988 Mercury Grand Marquis

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My car has 94576 miles.
My car has an automatic transmission.

Hello. You should start by looking into your vacuum and fuel supply. Both of these will have an adverse effect when pressing on the gas. There are several ways to test for a vacuum leak. The most efficient being with a smoke machine, but there are other methods you can try as well. The fuel pressure is best tested on the fuel line anywhere after the filter, typically at the fuel rail.

Place the gauge in-line and allow the gauge to measure while you run the vehicle. Compare the readings to the manufacturer specifications. You may need to attempt to recreate the symptoms in order to get a proper reading when the issue occurs. Carbon build-up can also cause acceleration issues.

I recommend having a certified mechanic, such as one from YourMechanic, come to your location to determine why the car is stalling and suggest any needed repairs.

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