bzimmer260

I have a 05 Mustang GT and the battery died yesterday. It had been pulling low for the last couple of weeks so it wasnt a surprise. I put in a new battery and it fired right up...but it seems to not go through its usual warm up sequence. RPM also come way down, almost to 0 when driving and coming to a stop...once off idle it drives fine but when coming to a stop the tach almost bottoms out. Do I need to unplug the battery in order to reset the computer? Am I dealing with a bigger problem?

sailing220

Do you have a custom tune? Try reloading it.

If not, it sounds like a throttle body or MAF issue. Check the connections for the TB and if it still doesn't go away, try getting some MAF/Throttle body cleaner and clean both of them.

I don't think that "pulling low" as you put it (I'm assuming this means not as hard) is a symptom of a dying battery, but if that went away after the new battery, who am I to argue? Ha..

ski

It may also be caused by the ECM re-learning the idle strategy, which is wiped out when replacing the battery. There's a procedure in the owner's manual for helping the ECM to do this after installing a new battery.