Noises from motor.....

[Butane08]

I have a 96' 7.3 with about 134K on the motor. I bought the truck from my boss this last summer and it was well maintained. It was completely stock when I bought it. I recently put a tymar intake and started to do the diamond eye exhaust. (Right now I am running just the downpipe intill a friend of mine has time to weld the rest of the exhaust.) Anyway just recently the truck has been making a funny noise when you let off the accelerator and then get back into it. Its almost like a vacuum sounding noise. When i get back into the accelerator it sounds like a sharp "sucking noise" then it goes away till the next time i coast. I dont know if this is from only running the downpipe or if the truck is starting to have serious problems. Help please! Thanks!

[Butane08]

I have heard this could be the exhaust back pressure valve? Could this be the loud whoooooshing sound i hear? I usually let the truck idle for 30-45 mins before driving it but it does not get driven but 2-3 days a week. Is there a way to unhook the sensor and will this hurt the truck?

[EArmsF350]

I see no one replyed to you. It does not hurt to unhook the EBV. It is there to help warm the engine. On a 2001, which I know is somewhat differant, the EBV is powered by a small 2 wire plug in just under the turbo on the turbo pedistal. Just unhook it and try running your truck when it is cold and see if it stops. If so you have an EBV messing with you. If you unhook it and the EBV is still in and out, you can tie the plunger open so it stops surging on you. You will most likely have a mechanical problem with the plunger and keeping it open will stop the surging. Hope this helps.