So I've got a 2005 vnl D12 engine. Sometimes when using first stage engine brake (epg) I hear a whistle. I've checked for boost leaks, there are none. EGR clamps are tight. Replaced clamp from epg/turbo. Any thoughts?
Also my fuel mileage is kind of crappy. I've been getting 5.6 for last 20k miles. I've replaced turbo, intercooler, various hoses and clamps, Egr FIX, k and n filter. Fuel pressure is ok, injectors are ok. Any ideas on this? Maybe the above issue is related ?