1999 Chevrolet Suburban

Engine Performance problem
1999 Chevy Suburban V8 Four Wheel Drive Automatic 189000 miles

1999 Chevy Suburban V8 Four Wheel Drive Automatic K1500 5.7 L Vortec Engine. Engine will start and runs fine when cold.
After1-2 miles driving engine, it will not come up to
speed. When I go to start it back up their will be no power but the lights and electrical will flicker on and off and will automatically set the settings to cd and time to 1: 00. Also today the electrical locked all of my doors while I was sitting in it. The battery was put in in Oct04. I replaced the post on the battery 2 months ago. When I go to restart it after it has died on me I have to loosen and retighten the positve post on the battery to get it to start. I had the battery checked today and it read 588/690 AMPS. I know that reads a little low and the battery should be replaced. I put it on a computer and it read P0405 EGR Sensor " A" Circuit low. I recently did an oil change and changed fuel filter hoping to get better mpg. I have had this problem in the past but it always seemed to fix itself. I replaced the starter 2 months ago when it came to not starting at all. I would appreciate all the help possible.
September 5, 2010.

If the battery was replaced in 04 that means it's 6 yrs old. Batteries are good for about 4 years then it's on borowed time. When a battery go bad the computer is always trying to find good voltage. First replace the battery with a good one. And Clean all your grounds- body and engine. Batteries have to be load tested with a load tester. If your voltage drops steadily to lower than 9 volts and if it only reads 12.2V initialy then your battery isn't any good and will set a bunch of codes or make it seem that you have problems. Of course you may still have the problem but you need to start with a good battery.

Sep 9, 2010.