Newbie Question, exhaust back pressure valve
I was recently came in to ownership of a 1996 F-250 7.3 liter power stroke. I had second thought of owning a Diesel, but now I'm hooked, I love this truck, but Anyway I have question for you all.
Just recently when the Temp hits or gets below 35 F, out, when I start the truck, there is a loud "sucking" sound coming from the tail pipe, I does go away if I let it sit and warm up for 20 mins, But then as I drive it, the sound returns, and the Rpm drop 500, and the motor bogs down a little, I give it a little more loud petal, and it goes away.
My question is, I think that its a problem with the exhaust back pressure valve, Well What does that valve due, and will it harm the truck if it gets wired open??
The fluids are fine, actually just changed the oil, There is no cat or muffler, on the truck, just a 3.25 inch system. The truck start and runs fine, Also the truck has been chipped, I have no Idea what the chip is or what, i was told by the original owner that its to help with mileage. Thank you all ahead of time for any help you can give me.