2005 Mercury Grand Marquis hesitates when stopped at red light while pressing the accelerator, what is the cause?
The TPS could have. Bad spot in it, once you get over the initial stumble does it run ok.
Yes it runs ok till slow down to a stop again.
If you want to track it down for sure you may have to get the computer system "live data scanned" that way you could see what the ECM sees as the sensors send their signals to the computer.
sounds like map sensor very common to go bad very easy to replace two screws
Thanks I will get that checked out and let you know if that's the problem.
Possible Manifold Absolute Pressure Sensor (MAP Switch). It will jerk at low speeds and run smooth at speeds above 45 +-. Some times it shows no problems codes when checked.
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