griffvision

hey guys, update: I have changed the small air filter for actuator like joey mentioned, I have also replaced boost pressure sensor. still no change. checked tank vents also, all good. I am getting an active 6-4 code all the time, truck works fine sometimes and pulls great, seems like after it works for about an hour it loses power, making little boost. Any suggestions ? would this 6-4 code be any guidance

thanks Fjh, when diagnosing I actually put a 1" plug in there where the boost relief valve goes and the truck ran great, pulled great and pounded boost gauge every time, this is why I thought I had the problem corrected..... no doubt I did have a worn out boost pressure relief valve but thats obviously not my only problem. In thinking of it; it was when I installed the plug on first start up the truck coughed when revved at idle (almost sounded like Jake on) and put out blue smoke out the stack and back through the tube that connects to bpr valve, could this be an indication of stuck egr or something else ? truck has not smoked noticeably when experiencing low power issues, nor coughed, just gradually dies out. I have the small air filter on order to arrive tomorrow that joey has mentioned above, we will see what that does too

Thanks I have not, will try that tomorrow. thats the small one on drivers side of engine by side of frame rail? I did disconnect stainless air line going to actuator and there seemed to be lots of air, didn't pressure check it or anything though. Put a small bit of shop air to actuator and it moved rod up and down easily.

hi all, Long time lurker of posts, thank you all for the vast knowledge on here, I've used info many times, it is my First time posting; So I have a 2006 CXN613 vision , with AC460 CEGR engine. I have been having intermittent low power/ low boost problems with the truck, sometimes truck pulls great and makes 30+ psi boost, others can't get the truck to hold 5 psi. Seems to happen more frequently after about 1hr of use. I've had the truck to several garages, all to no avail. Some background on what has been done: I have checked for loose wires at eecu connectors (as this had been a problem causing truck to shut down while driving in the past) I have replaced and calibrated fuel pedal, all good. I have checked VTG operation visually and while driving with a GoPro, all seems good. I have disconnected and pressure tested charge air cooler and piping, no leaks. Fresh fuel filters, air filter, no fuel restrictions No current active codes (getting an occasional 6-4 flash code, but not corresponding with low power occurrence. I have replaced boost pressure relief valve, thought this was my issue as I tested it and it was weak, opening at 3-4psi; when I replaced valve, after first startup the truck sort of coughed and ran rough for a second putting out blue smoke, test drove the truck bobtail, it pulled like a race car (maxing out boost gauge I installed) , I was excited thought I had issue resolved. Truck went to work the next day, ran great for about an hour loaded then lost power. No codes present. Anyone have any suggestions on where I should look next.