So my old starter went out, after i replaced it the new starter worked well for about 2 days, now it sounds like its having alot of trouble starting. sometimes it is just not engaging at all when i turn the key, which is what the other one did before it totally died. i tested the voltage on the battery which was good, but as i start the car, whenever the starter almost dies the battery drops to like 9 volts, and i cant figure out what would cause so much drain as to suck that much power (except maybe the engine trying to start with incorrect timing?) any ideas??? please HELP

 

Check for corrosion on the main cable from the battery to the starter.
This problem caused me a lot of headaches.

Check the voltage where the cable connects to the starter relay to see if this is a problem.

 

probably didn't clean the mounting edges of the starter and the engine when you put the new starter in.

You need to make sure that the body of the starter is grounded will to the engine, so clean off all the paint on the edge where the starter mounts too the engine.

 

+1, corrosion in either the grouding of the starter or the main power cable are the two most likely things.