my 03 dakota 4.7 started getting a goofy idle yesterday and i'm not sure which part should be replaced since i'm not getting a cel for it. at a cold start, it revs to around 2k then drops to about 500 or so and lopes pretty hard. as soon as it gets put in gear, it revs to about 800 or so. it has also stalled a few times from idling too low. when warm, it idles between 300-600 and lopes. if i put it in park immediately after driving for a while, it will stall. if i drive it while the engine is still cold, it drives sluggish and seems underpowered.

anyone have any ideas? from searching the internet, similar issues were caused by iac or tps sensors being dirty or bad. i don't have a lot of money to spend right now so i'm trying to get an idea of what's going on befpre i spend money on it.

thanks to anyone with any advice

 

I would start with the tps.

 

test the TPS, back probe it with a volt meter, there should be a steady swoop in readings with you opening the TB really slowly. if readings jump around thats also a sign that its gone bad, oh yeah the key has to be in the ON pos.

but my bet is that the IAC is bad, since you are saying its dying at idle. you can take it off and clean it.