Hesitates and sometimes dies after warming up when you accelerate. on 2000 Mercury Grand Marquis

Our 20000 Grand Mar. hesitates and sometimes dies after warming up when you accelerate. We have had new plugs, new gas filter, new fuel pump and replaced four sensors, including the throttle position sensor. I thought the OD was not working properly ,but after replacing the Throttle position sensor it is fine. It runs great until it warms up , but after about 10 min. it starts to hesitate and will die after acceleration from a stop.

by in Long Beach, MS on September 09, 2010
3 answers
ANSWER by on September 09, 2010
Check for any Check Engine codes. There are several things that could cause these issues. For example, a vacuum leak, a defective Mass Air Flow Sensor etc.
ANSWER by on January 06, 2011
I,since 2 week i have the same problem with the same car,(mercury grand marquis 2000 141000km)did you know this car have a serious problem with CRACK PLASTIC INTAKE MANIFOLD some coolant may suck into cyl.2,3,4 code p0302,303,304 try this,when the radiator is cold, simply remove the radiator cap and retest,if the car ran ok you have a crack intake.
ANSWER by on May 01, 2011
Mine was having the same problem. Come to find out all that was wrong was the Idle Air Control Valve.
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