First off I'm not much of a mechanic and need some help. I just bought a 2001 ram 1500 with the 5.2. When the engine is cool it runs terrible (has no power, is missing and feels like it is going to die) but after about 15 minutes of driving it smooths out and runs like a top. The guy I bought it from said it has a vacuum leak but I can't find it. Any inexpensive suggestions?

 

I'd check your IAC sensor located in the back of the throttle body, it regulates your idle. Few screws remove it, if the sensor it self is black, replace it. If not try cleaning it off and putting it back in, also make sure you clean around the hole it came out of and well. Now the part your not gonna like...if you manually open the throttle and look down the throttle body into the top of the motor. Run a flash light in there, and see if you have any oil pooling in there. IF so which you probably do cause they all do, then your going to have to repair your plenum gasket. Which will run you around $400-800 at a shop if you can't do it yourself. Now replacing the IAC might help with your idle, but having a blown plenum will cause missing and substantial power loss, and atrocious fuel economy. Now, if its really a vacuum leak, run the motor and put your ear in there and listen for any unusual hissing or you know "air leak" sounds. IF it feels like its going to die when you come to a stop though, its most likely the IAC, or in some cases your fuel pressure.

 

It seems to idle fine but the trouble starts when I step on the gas. Would the IAC still be part of the problem?

 

Unplug the front oxygen sensor (upstream of the catalytic converter) and go for a ride. Expect a check engine light due to the unplugged sensor. If the symptom goes away, replace both oxygen sensors using only dealership parts, Denso, or NTK brands. Be sure to disconnect the battery while replacing the sensors so the PCM will have to learn the characteristics of the new ones.

Oh yeah: Don't succumb to the temptation to just leave the sensor(s) unplugged. Doing so will lead to expensive bad things in the future.

 

if its when your stepping on the gas then i might suspect a fuel issue or something with the ignition