tranceworld1216

2008 mustang gt. 39000 miles. Auto. Bama tuner. The rest is stock

Been running the tune for a year now. Pulled it out of storage this spring and battery was no good. Got new battery. Ran great, no issues. Last week as I was leaving work, went to start it, and it seemed that the battery was dead. Turned over twice, then nothing, then clicking (starter clicking?) Then turned over again, and again, then started. lasted all of five seconds. Drove home with no problems. Next day tried to start and same thing. Gas gauge said quarter tank. Turned off and back on and started right up, gas gauge read half (true).
Today, same slow start as the night at work, gas gauge normal. Turn off and start right back up and slow start is still there.
At first I was thinking problem with fuel pump, since it seemed as if it wasn't getting gas. Also has original fuel filter. Still have to check the battery with a multimeter, might just take it to get tested at autozone.
Also plan on setting tune back to factory, don't think this is the problem since it was running fine before and had no changes.

No codes have been thrown.

What are your thoughts?

Nuke

Slow cranking has nothing to do with the tune. First thing I'd do is check your battery terminal voltage after the car has sat overnight so you're not seeing a surface charge. You should be seeing 12.5-12.7 volts for a healthy battery, BUT a VOM measurement can not detect a sick battery. Then, I'd remove the battery terminal clamps, clean the posts and clamps and reconnect everything. A dirty terminal adds resistance and reduces available cranking amps. If the problem persists, have the battery and alternator load tested. Your "good" battery could have degraded due to a faulty alternator and we all know how poor the charging systems are in these S197's.