Audi Repair: AUDI A4 1.8T Starting Problems, oem replacement, audi a4

Question
Hello:
I am in California with a 2005 Audi A4 1.8T automatic with 60k miles having starting problems.  At 58,000 miles I replaced the battery at the request of a mechanic because the battery was leaking and the battery seemed to be getting weak during starting.  I put in a new OEM replacement battery and the starting problem is slowly getting worse by the day.  It now takes 3-5 seconds for the car to start as it sounds like the battery is almost dead when starting, yet my lights still work fine when the car is off, so my suspicion is that it must be something other than the battery.  75% of the time this starting issue occurs, while 25% of the time it starts like a normal car should. It happens whether the car is hot or cold. I don't know where to start.

Answer
This sounds like a problem with the starter itself. However check the current capability of the battery, if it is new, it should be OK.  Check you get 14 Volts on the battery when the engine is running, to show that it is charging OK, and if those check out OK then the starter motor is next to check.  Let me know,  Jan