I've got a 2003 Dodge RAM 1500 SLT with a 4.9 liter. This is truly a fantastic truck. I love this truck to death. I know some other reviews are crying about gas mileage with the economy in shambles but just like with the mortgage crisis someone needs to say "uhhh... hey moron. If you make 20k per year why did you buy a 200k house?" The same goes for trucks. You looked at it, you got all excited, you bought it - deal with it.
Unlike a lot of wishful thinkers I actually use my truck as a truck. It's gone on hunting trips, off roading, a camper shell rendered it as a mobile shelter for a week in the wilderness, it's hauled wood, game animals, my dogs, and boats and jet skis. A friend used it to haul a huge hulking beast of a bull to another farm when his truck was broke down. It hauls everything with no problem. And it does all this with comfortable seats and a roomy interior with everything placed just right within reach for a large fellow like myself. I am rather big, and it is wonderful after so many years finally having a vehicle that I fit in. My days of yoga contortions getting in and out of vehicles are over!
There is not a thing that can hurt this truck. It goes up the steepest hills and mountain sides with ease. It offroads well. And I mean off road, not dirt roads. I've crossed creeks at full throttle with it. I've even been washed off a road in a flash flood that almost killed me. But not the truck. Nothing can kill this thing. I don't baby this thing at all. She's a good machine. And beautiful jet black and shiny chrome. All the scrapes and scratches from rocks and branches don't take that appeal away from me. She's the best truck I've ever had. She's my Helga.
The pulsating is normal. It's the pressure changing quickly due to the air being sucked out of the cab (negative pressure) and then then being equalized or over-shooting to a slightly positive pressure.