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Condor1970
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I wonder if they disconnected the battery to do the diagnosis but didn't properly reset the ECU when finished?
If that's the case, then you can reset the ECU by disconnecting the Pos+ battery cable, and ground it to the Neg- for about 15-20 minutes to clear everything. When you plug it back in, start the car, and let it idle with the A/C off, and DO NOT touch the gas pedal. After idling with A/C off for about 5 mins, turn the A/C on, and let it idle for another 5 mins. Then turn off the car. Take your foot off the brake and hit the power button to turn on the power without starting the car. With the power on, press the gas pedal to the floor and hold it for a few seconds. Do this several times to tell the ECU the range of the gas pedal without the car running. Then turn the power off.
When finished, you can start the car, and drive it normally for the first day or two, without revving much above 3,000rpm to get all the lower rpm driving conditions programmed. After doing this for a couple days, then start playing with the throttle and having fun a bit more.
If that's the case, then you can reset the ECU by disconnecting the Pos+ battery cable, and ground it to the Neg- for about 15-20 minutes to clear everything. When you plug it back in, start the car, and let it idle with the A/C off, and DO NOT touch the gas pedal. After idling with A/C off for about 5 mins, turn the A/C on, and let it idle for another 5 mins. Then turn off the car. Take your foot off the brake and hit the power button to turn on the power without starting the car. With the power on, press the gas pedal to the floor and hold it for a few seconds. Do this several times to tell the ECU the range of the gas pedal without the car running. Then turn the power off.
When finished, you can start the car, and drive it normally for the first day or two, without revving much above 3,000rpm to get all the lower rpm driving conditions programmed. After doing this for a couple days, then start playing with the throttle and having fun a bit more.
Lime1GT
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As said in previous reply; You might want to try this since the battery was disconnected for so long while repairs were being made.
Cobra Jet
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You may want to review this TSB, as it sounds like the issue at hand. As noted above the battery reset might work, but according to the TSB, it might not.
Bluemustang
Well-Known Member
This is interesting - this sounds logical. The 15-17 cars have adaptive learning as I assume the 2018 does too. It adapts to many parameters including the driving preferences.
Sometimes when I am doing a lot of commuting to and from work and going slow without going WOT or anything like that, and then suddenly I go WOT one day, it reacts sluggishly for a second. The next time I go to do it, it pulls hard again. A KAM rest usually helps several months to help the car re-learn. Usually the car feels more peppy.
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