Own a 98 Ram 1500 with a 318 5 speed manual tranny. While accelerating with the AC on the air flow out of the vents stops and then resumes once I'm off the accelerator.I have owned it since new and have never expericened this problem before. Down here in Texas we need all the AC/airflow we can get.

 

Vacuum leak. Probably plenum gasket.

 

search for "wild vents"

 

https://dodgeforum.com/forum/2nd-gen...ild-vents.html

 

come on zman. ya gotta teach em to fish

 

Wishful thinking! LOL

 

Now im just the opposite, with heat on mix between floor and defrost, if i am at low rpm's and in OD and i ease into throttle i hear that the defrost sounds to blow harder. engine is fresh from top to bottom with hughes plate blah blah blah..

 

That could just be the alternator putting out more to the battery. Maybe your battery is weak or alternator for that matter. Do your headlights dim at low rpm?

 

havent really noticed but next time i drive at not ill pay attention. Oh wait it does it at night, during the day, end of the month, begin of the week, LOL all the time anytime.

 

LOL, I'd say your battery is starting to go.