I have noticed a rather loud suction/vacuum sound in my 2000 PSD 250 when the accelerator pedal is slightly to moderately depressed. It goes away when more pressure is applied or if no pressure is applied. Has anyone else heard this noise and/or know what it is or if it is normal?

 

I have heard the same noise as you are describing but my husband never hears it and says I am just hearing things. I drive this truck everyday and i try to tell him that this is not normal but he just does not hear it. We have had our 99 PSD for almost a year and i have just within the last 3 or 4 months noticed it. I will be watching to see if others respond and if this is normal or not.

 

I HAVE BEEN DOING A LOT OF RESEARCH ON MY NOISE PROBLEM. IN FACT IM TAKING IT BACK TO FORD TODAY. I HAVE A 99 CREW, F350, 4 BY, PSD BUILT IN FEB 99. 8000 MILES AND NEVER TOWED A DARN THING YET. I ALSO HAVE A BOOST GAUGE ON MY TRUCK. THE PROBLEM STARTED DURING COLD WEATHER, AND WHEN IM DRIVING ALONG AT A SLOW SPEED WHEN NO BOOST IS BEING APPLIED BY THE TURBO, USUALLY APP. 15-20 MPH, I HEAR THE NOISE OUT THE TAIL PIPE. YES IT STOPS IF I THEN ACCELERATE HARDER. IMPORTANT: I ALSO PULLED THE INTAKE TUBE OFF OF THE TURBO BEFORE IT GOES INTO THE INTERCOOLER AT THE RUBBER GASKET AND FOUND OIL IN THE TUBE!!! THAT MEANS THE SEALS ARE SHOT IN THE TURBO. CHECK YOUR TRUCKS, THAT IS THE NON-INSULATED PIPE. OUR DIESELS HAVE A 130 SECOND DELAY TIMER DURING START UP, COLD WEATHER, THAT KICKS ON THE CHOKE, AND THEN IM EXPERIENCING THAT NOISE AGAIN,AND SOMETIMES THE RPMS WILL SWING UP AND DOWN 400 RPM. I BELIEVE THAT IT IS POINTING THE WASTEGATE. I HAVE ANOTHER BUDDY THAT HAS JUST ABOUT THE SAME TRUCK, AND HES HAVING THE SAME PROBLEMS TOO. THE DEALER DID NOTHING TO HIS TRUCK YESTERDAY. THERE IS DEFINATELY A PROBLEM

 

I GOT MY TRUCK BACK FROM FORD, AND THE NOISE CREATING PROBLEM IS THE RESULT OF THE "EXHAUST PRESSURE VALVE SENSOR" BEING BAD. THEY HAVE ORDERED THE SENSOR AND I WILL TAKE IT BACK IN TO GET IT REPAIRED