05 F-550 surge under load

[bigmk01]

I have an 05 f-550 that surges under a load from 1500-2000 rpm. Usually does it under acelleration in 2nd a 3rd gear. ( Manual Trans ) But today while going a really steep hill in 1st (not low) the truck began surging violently to where it was shockloading the drivetrain. So I had to stop and climb the rest of the hill in low. This truck is stock with no mods. gvw of 21K pounds. Pulled up an error code of P0528 I think, I didn't write it down. But when I looked it up it said something about cooling fan. Any input would be great.

[bcoakley]

Mine did the same thing- only under a load and only at low rpm such as 1500-about 1800. I think this engine does not like it much under 2000 rpm, especially when towing. Mine sounded like it was having multiple "turbo farts" too. I thought it was a wastegate, but I'm told these engines do not have a wastegate. I believe it is due to too much boost for the amount of boost needed by the engine at that particular rpm. I got the computer update that makes that "noise" for about 20 seconds after shut down. That took care of the problem and I noticed a less amount of boost in the same load situation. But with my programmer on the middle setting it still does it (when towing), so I just never let the rpm go down less than 1800rpm and it doesn't occur.