i left the house in a hurry and left my keys in the truck with the ingition on. well when i came back the batter was almost completely dead. so i got out my jumper pack and fired it up. well it started right up and reved to around 2,500 rpms and stayed there no matter what i did. i checked all the cables and the tb and that all looked fine. also by the way the tb was closed during all this. well i shut it off and turned it back on a few times and it would keep doing it. then i unhooked the battery for a minute and it stopped. anyone know what the hell that would have been. was it like just a random pcm glitch[sm=wtf.gif]

 

sounds like the pcm controlling the engine to charge the battery. you probably had a loose connection that wasn't passing the current completely. were the battery connections HOT when you pulled off the battery? could be rusted terminals.. that happens and then you don't get the connection to charge.

my truck revs up to about 1100 rpm when i start it because of the amp drawing a lot of juice on start up.. still need to get a cap.

the pcm will controll the engine so that all your electronics will be powered aka run the alternator.

at least that's my best guess.

 

Once I had a similar problem with a battery that had a broken cell. I used the jumper unit and my ECU turned completely crazy and the engine kept running at 2500 R.P.M. too. I shut it down and brought another car to start my truck from another battery using jumper cables and it started normally. I shut it down again and used the jumper unit and it turned my ECU crazy again. I again shut it down , got a new battery and the problem was fixed. Later a friend who is a mechanic told me that sometimes the jumper unit generates wave signals that can confuse the ECU making it think the wave came from a sensor. I'm not sure if this is true, but maybe this will give you a hint.

 

It's possible the IAC valve got confused with the loss of voltage with the key on...just another possibility.