05 VOLVO truck VED D12 engine lacks power and makes 4mpg.. what is wrong?

Volvo uses an aluminum can with a big piston in it to restrict the exhaust gas for a Jake break. The piston has a nylon sealing ring that gets cooked and the piston gualds the sidewall and restricts you exhaust like stuffing a potato in a car's tail pipe. No exhaust, no intake air, poor fuel economy and little power. The vacume control modual is also another cause of this same problem. The fix isn't cheap, but neither is fuel. Replace them "BOTH" and you'll fix "BOTH" your problems! For reasons I could not begin to explain, Volvo dealers can never seem to figure this out and you have to INSIST they remove the Jake can and check it.

 

Take the piston out of the Jake and psychically check it. The Jake is seemingly worling when you apply and release it, but it isn't opening all the way. I've owned a 99- 770, a 2002=770 and a 2004-77o all with the VED465's in them and all three had your exact problen ant that was the fix on all thre. The 04 I got for peanuts because the origional owner had been fighting poor economy and power and Volvo was bleeding him dry and not finding the problem. If you take the can apart rather it's good or bad it'll be obvious either way. The control mod either has to be checked out by Volvo or just try another one and see if it cures it.

 

if you have a miss it should have been apparent from the start I would have thought. Also, usually, if the miss is caused by an injector there is no mistake it's missing. lol

 

Well, as we know only too well, anything can and usually does happen with trucks but my money is still on the Jake as that is a real problem with the VED's and gives you your exact symptoms. Wish you well and hope that fixes it.

 

My money is on the intake boost/temp sensor

 

just wondering what was the problem, since it seems I have a same problem on my truck, loss of power, decreased mpg, and weak ex brake..