Ram 2500 hissing when accelerating

Hello, new poster here. I searched and didn't see this discussed elsewhere, so forgive me if this is a dupe.

I was looking to possibly buy a 2000 Dodge Ram 2500 extended cab 4x4 with the 5.9 V8 engine with about 50,000 miles. It has the towing package, camper package, and the snow plow prep package. It seems like a really nice truck except for one thing...I noticed that when I accelerated, it has a fairly loud hissing sound of air that seems to come from the vents (and the vent/air is not on). The sound seems to diminish some as the engine gets warmed up, but it never goes away completely. The sound does not seem to be noticeable when I am at a constant speed (i.e. not accelerating). I have test driven a few Dodge Rams around those years and haven't heard that noise with any of the other ones, but none of the other Dodge Ram 2500's were this fully equipped. Does anyone have any ideas what might be causing this noise? Is there anything that I can easily check when I go on another test drive with that vehicle? Thanks for any help or advice that you can provide!

Well, upon further discussion with the dealer, it seems someone else mentioned that sound too. They think it's the air intake housing(?) that wasn't connected properly after some work done causing the hissing (How ironic because I just fixed that same spot on my own truck - I don't remember it hissing bad though). They're checking into that and are supposed to let us know. At any rate, we have an inspection scheduled for the truck if that doesn't seem to fix the problem.

Keep your fingers crossed that that fixes it because this is a sweet truck except for that one problem....

Very odd, but does sound like it's an intake noise. YOu buying from a dealer then? Make sure it's right before you leave the lot!!

Mine hisses as well but only when cold. I just noticed though that the rubber gasket that sits between the throttle body and air filter housing is missing.

Hello, new poster here. I searched and didn't see this discussed elsewhere, so forgive me if this is a dupe.

I was looking to possibly buy a 2000 Dodge Ram 2500 extended cab 4x4 with the 5.9 V8 engine with about 50,000 miles. It has the towing package, camper package, and the snow plow prep package. It seems like a really nice truck except for one thing...I noticed that when I accelerated, it has a fairly loud hissing sound of air that seems to come from the vents (and the vent/air is not on). The sound seems to diminish some as the engine gets warmed up, but it never goes away completely. The sound does not seem to be noticeable when I am at a constant speed (i.e. not accelerating). I have test driven a few Dodge Rams around those years and haven't heard that noise with any of the other ones, but none of the other Dodge Ram 2500's were this fully equipped. Does anyone have any ideas what might be causing this noise? Is there anything that I can easily check when I go on another test drive with that vehicle? Thanks for any help or advice that you can provide!
My 1998 Ram created a hissing sound on light acceleration at about 100k .It sounded like a vac. leak from the AC vents.While it was in the shop for a fuel pump change, I had them look into it. They cleaned the throttle body and fixed the problem.

Thanks for your replies everyone.

Yes the truck was at a dealer. I can only assume that that was the actual problem, because the salesman "forgot" to give us a call when the repairs were done and he never actually said if that fixed it. They assured us they were holding the truck for us (we offered money to hold it, they said no need, but were holding anyway -- we'll know what that means next time). They had no problem with fixing the few issues we pointed out about the truck. Thursday (the day before we were to go back and have it inspected and everything) my husband called to check the status on everything and the salesman proudly informed him that the truck was sold on Wednesday (and he made it a point to say that he got the full lot price for it versus the "internet price" we were going off of). Needless to say, we were NOT happy about that stunt, for if we were told the truth that they don't hold anything for anybody, we would have made it a point to go back earlier. Long story short, we've got a couple more trucks to look at in the next few days, so I'm sure we'll find something.

For those that care about this sort of thing so they can avoid the place, this was a dealer in SW Columbus OH, about 3 miles south/east of I-71 on I-270. I don't know if I'm allowed to post the actual name of the place, so if anyone wants to know it, email me at kwapp at hotmail dot com.