Car dies when pressing accelerator

mercury
grandmarquis

#1

Hi. This problem just started recently. I’m sitting at a stop light, car is idling fine. Lift my foot off the brake and the car dies when I press the accelerator. This only happens when the car is not fully warmed up. Shows one bar on the digital temperature indicator. To start again I have to feather the accelerator pedal. Then it will die as soon as I shift into drive. As soon as it warms up just a bit more, no problem. Any ideas?


#2

Sounds like the coolant temp sensor is a bit askew, telling the PCM the engine is warmer than it really is causing a lean condition. What year?


#3

'96. Less than 140K, well cared for. I wondered the same thing. Seems like
the the temp reading jumped to 4 bars after just another couple of blocks
driving.


#4

If you have a way to test resistance of sensor I will give you some specs. At 70 degrees f. you should have close to 35 k ohms. At 100 degrees 16 k. At 150 6.2 k. At 200 2.3 k.


#5

Some cars have one temp sensor for the gauge and another for the engine control system.


#6

Thanks guys. Based on some odd temperature readings, low cost of the sensor and ease of replacement I went ahead and changed the sensor. This morning - didn’t help. Wondering now if the thermostat could be the problem. I drive about 3 miles with the temperature reading just one bar. Then within just a minute it goes up through 2, 3 and finally to 4 where it has always read in the past. Think the thermostat could be sticking and opening late and all at once?


#7

T-stat is not supposed to open until engine reaches temp. I doubt that’s the cause. Even if T-stat is stuck open, it wouldn’t cause this concern. You need to test fuel pressure. The highest fuel demand will be cold on accelleration, so that’s where I would go next. You should have 35-45 PSI key on engine off. Also as Shanonia has stated, there is two coolant sensors on yours. One for computer, one for gauge. Did you replace the sensor with the round connector, or the one with a more square connector. Round one’s for computer, squarish one for gauge.


#8

I replaced the square one. Temp gauge behavior is definitely off from usual. Usually transition from one through 4 bars takes a few minutes between each as I’m driving and warming up. Now from two to four in less than a minute.


#9

Well, I’m embarrassed as hell. Went to have another look under the hood and discovered coolant about a gallon low. Topped off and the problem disappeared. Guess low level was causing the incorrect reading. Lesson learned: check the essentials first. Thanks for the input. Related - I had to replace the radiator 2 years ago. No Ford parts available, generic brand aftermarket part used with only a 1 year warranty (from local Ford dealer). If the generic radiator is the cause of coolant leak now, how do I go about finding a worthwhile replacement?