2002 sunfire stalling problem

[jay0016]

My sister has a 2002 pontiac sunfire, the problems started when the battery kept getting drained, the alternator was older and could use to be replaced, but even after replacing it the battery would still be drained. I took a multimeter to test each fuse found out the radio fuse and instrument cluster fuse were drawing from the battery(when the car was off). Unplugged the radio and this problem has stopped. However the car will stall every couple weeks found out that the fuel pump relay was making a bad connection in the fuse box, did my best at tightening up the connection and the problem so far has not resurfaced (stalled last time about 4 days ago). I was going to replace the radio for her with an aftermarket stereo when I found out about the auto data bus system or whatever genius hotwiring prevention GM created. Could this system be causing the problems, or is it more likely the two problems are unrelated? The fuel pump was replaced about a year ago so I'm fairly confident the relay was the problem but how common is an electrical issue somewhere between the fuel pump and relay?
Thanks for any information.

 

[jay0016]

Also the car seems to be idling very low between 480-620 rpm, and when driving at decent speeds and taking your foot off the gas the car drops straight to idle usually in my experiences doing about 40 mph the car should be around 1300 rpm or so until a downshift this does not occur.

 

[melsg5]

There is a RAP system, retained accessory power, which could cause the battery to go dead.
http://www.extendedgmwarranty.com/owners-manual/pontiac/2002-Pontiac-Sunfire.pdf

Concerning the stalling problem, do you have a check engine light on? The stalling can be caused by a number of components, Throttle Position Sensor, Idle Air Control valve, etc. How about vehicle maintenance, air filter, fuel filter, spark plugs?

 

[jay0016]

The tps may be causing the low idle problem, only see the car on weekends. There is no check engine light, and i'm confident it's not a regular maintenence component. I was thinking of more of an electrical issue rather than mechanical but both are definitely a possibility.

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[XXWoodmanXX]

Wife's '04 was doing that same thing, too. Replaced the battery 3 times before we found the issue. Her car had a really weak ground connection from the battery to the chassis ground. Removed the lead, cleaned the corrosion/paint, re-installed lead with de-ox grease, and it's been great ever since.

Seems like it was causing unnecessary loading of the battery with the ground resistance.