Yesterday I tried to start my 2000 Dodge Ram 1500 after it sat for just over a month. I turned the key and hear the typical sound of a dead battery. I've left it sit like this before and the battery has drained so I figured it was the battery. So I go and get my jump battery. I hooked it up and it starts right up but never idles just cuts immediately. I try a few times with the same result. So I try once again but give it a little gas to see if it'll provoke it into a start. It starts and revs like it should then when I let off the gas it dies. The fuel pump sounds like it's functioning normally. I will check fuel pressure later. The lights, dash, and headunit all work so it's getting the charge. I have no idea where to even start. Any ideas?

 

My friends silverado was doing this recently It also had a dead battery. The battery was replaced and it stopped acting up. I think the alternator was putting too much strain on the engine and stalled at idle. Hope this helps.

 

when you give it gas, its causin that alt to work harder than idle charge. Thats why it wont die. At idle, the alt is not strong enough and is causin it to cut off. Id pull the alt, and take it to advance and have them check it. Also get a new battery while your at it.

Your fuel pump normally wont give you a warning when its done. As long as you hear that "whirr" at key on position, its fine.

 

Same thing happens to my rams with a dead battery. Just keep it reving around 2-2500 rpms for about 5-10 min to charge that battery up. Then it will run fine.

 

its your IAC? My truck was doing the same thing a couple of days ago

 

not to be captain obvious but check your oil... the same thing happened to me about 2 weeks ago I left the interior light on and truck was dead in the morning, went to jump it and it gave me some problems starting but started right up when giving it gas. Being puzzeled as I was I check the oil, lowand behold I was low after I dumped some fresh oil in she started right up and gave me no problem at all. I later took it to my mechanic who told me I have a bad seal... as he put it sorta the front equivalent to the rear main seal. so 225$ later Im good to go again. Good luck

 

I 2nd the IAC

Your computer lost it memory when the batt went dead. It was compensating for the worn IAC. You might be able to get it to relearn by feathering the idle for a few minutes.
Try and keep the idle around 500 with the gas pedal until it runs on its own.
Budget for a new IAC soon though

 

The battery is just about due to be changed but with a jump battery on I don't see how it wouldn't idle. Even with the alternator not putting out a good enough charge or completely dead it should at least idle for a few minutes. Besides all the electrical drawing features on my truck seem to function like they should, radio, lights, etc. Even with the jump battery off. I even see the volt meter on the dash jump to just under the first line when I turn the key to "ON" without the jump battery. With the jump battery I see the volt meter jump to about half way. So it's getting the charge. I checked the oil and it's right where it should be. The fuel pump seems ok, I can hear it make the typical noise it makes. Plus with the ability to rev I don't think it's the pump. I'm guessing it's the IAC. Is this something that needs to be replaced or is this something you can just clean and put back. How much do IAC's run? Also where is it located? Is it the black thing behind the intake under the airbox? I have the 5.2L 318.

 

IAC is on the back of the throttle body.
Costs $50-80 depending where you buy it.
Takes abt 30 mins to change but you need Torx sockets or screwdrivers to get the screws out.

 

I finally got around to swapping out my IAC. That was indeed the problem. I had a lot of carbon buildup and when I pulled the IAC out the rod was detached from the motor. I just wanted to thank everyone foryour help. Thank you. Runs just fine now.