My 2005 needed a new battery

[QuickSilverRW]

I bought my 2005 GT 5 years ago from the original owner with 5,200 miles and now have 7,400 miles.
For the last few years I have had a battery tender keeping my battery topped off and had not started the car an half a year. When I wanted to drive it two weeks ago it turns out that my tender was unplugged and battery was dead. I finally started the car with a 60amp boost. I let the engine idle for 5 minutes then started driving. After a mile I saw that the "check engine light" was on. Then the engine started missing and finally stopped, I towed it home and ordered a new OEM Optima 12v battery. After charging the new battery to 12.8 volts and installing it the car started right up. After letting it idle for five minutes I tried driving it and when the accelerator was depressed it ran rough and did not have any power. It stalled and did not restart easily. after a few tries it restarted but still had no power and did not seem to have positive supercharger boost. I am scared and desperate for suggestions. Thanks in advance

QuickSilverRW

 

[MontanaMoose]

I can’t say I have had that issue. I would however caution about using the battery charger to start the car. The dash cluster is VERY temperamental and I believe that the best way to have it go up in smoke is to have the dirty power of the charger. Ie either jump the car from another running car OR slowly charge the battery and wait. But don’t do the start setting on a charger.

Just my 2 cents

Also for what it is worth I put an interstate in mine like 12 years ago, so long as I plugged it in to a trickle charger by March 1 it started fine when the snow finally melted, and starts fine all summer without the charger.

 

[twobjshelbys]

This is already got traction in your other post

 

[QuickSilverRW]

Thanks MM, I appreciate your advice. I am an engineer but not realize that I was taking chances by using higher amperage on the charger. I am at a loss as to what to do next. I am thinking of buying and engine diagnose meter and looking for feedback. Does anyone know if our '05 cars will give data to a code reader and how to connect the reader? I an thinking that maybe my fuel pumps are not working.

 

[twobjshelbys]

Thanks MM, I appreciate your advice. I am an engineer but not realize that I was taking chances by using higher amperage on the charger. I am at a loss as to what to do next. I am thinking of buying and engine diagnose meter and looking for feedback. Does anyone know if our '05 cars will give data to a code reader and how to connect the reader? I an thinking that maybe my fuel pumps are not working.

Did you look at the other topic https://www.fordgtforum.com/forums/threads/1fafp90s45y400699.39166/ where I suggested you get a Bluetooth OBDII reader.

 

[nota4re]

I am at a loss as to what to do next.

What part of the Country are you in?

 

[twobjshelbys]

Did you check the air box and the Mass Air Flow sensor.

 

[Redfire03]

Simple thing, but are you sure the battery is installed correctly? Both positive and negative connection are tight and installed completely?
Did you check the ground and clean it off and re-tighten (should do either way)?

 

[dshears]

I bought my 2005 GT 5 years ago from the original owner with 5,200 miles and now have 7,400 miles.
For the last few years I have had a battery tender keeping my battery topped off and had not started the car an half a year. When I wanted to drive it two weeks ago it turns out that my tender was unplugged and battery was dead. I finally started the car with a 60amp boost. I let the engine idle for 5 minutes then started driving. After a mile I saw that the "check engine light" was on. Then the engine started missing and finally stopped, I towed it home and ordered a new OEM Optima 12v battery. After charging the new battery to 12.8 volts and installing it the car started right up. After letting it idle for five minutes I tried driving it and when the accelerator was depressed it ran rough and did not have any power. It stalled and did not restart easily. after a few tries it restarted but still had no power and did not seem to have positive supercharger boost. I am scared and desperate for suggestions. Thanks in advance

QuickSilverRW

My GT did the same thing as yours. Interesting, as I had almost the exact same mileage as yours. I replaced the MAP sensor and the problem went away. I first tried to clean it but that did not work.

 

[dr914]

I never recharge a battery still connected to the system