I have a 97 ram with a 318 in it and when the motor is cold it runs amazing. But once it warms up it feels like its a V6. I mean I have to give it all it's got to get up to speed when it's warm and half or so when it's cold. What could cause this?

 

Cat?
Pre-cat 02 sensor?

 

^^ Great place to start. Disconnect the pre-cat O2 sensor, and see if it runs any better. If it does, replace the sensor.

 

Ill try doin my O2 sensor first, the post cat sensor is new.

 

Mine gets a rough idle when its warm and especially in hot temps outside. Never figured it out and couldn't find any help that could either. Strange. Hope you can solve your problem. Sorry for not offering any help

 

ECT could be a problem. But my money is on, well you all know what I'll say next.

 

The title of your thread sounds like a classic case of a vacuum leak. More air coming in is matched with the enrichment cycle of your computer but when fuel lessens because it is hot it will run like sheeeeeet. Do you have a high idle or any sort of indication of a vacuum leak when hot?

 

Nope, it idles about 600 all the time and no sign of a vacuum leak