Losing power while driving lack of fuel. Fh12 2003. Cleaned…

Hi, My name is***** will be glad to help. We can follow up as needed on here. Professionals are not employees of the site but users of the site and help on here as time allows depending on their daily schedule. Sorry to hear you're having these troubles with your Volvo truck. These models usually have the D 12 engine in them. Common failures are the fuel transfer pumps with these engines. I see that you have changed what you are calling the pressure pump. I'm assuming it is the high-pressure injection pump? If so, the fuel transfer pump is a very common failure in you will also want to check your fuel lines between your fuel tank and your fuel injection pump for any leaks or restrictions whatsoever. You will also want to straighten out any dry rotted or cracked fuel lines that could be sucking in air. Thoroughly inspect your fuel filter housing for any potential leaks. It would be a good idea to reseal your fuel filter housing. If all of this checks out okay and you have good fuel supply to the injection pump in your injection pump is new but experiencing low power, I suspect you may have a problem with your air intake piping and possible turbocharger causing low boost pressure. Check for any leaks or restrictions with your air intake piping as well as doing a thorough inspection of the turbocharger with the intake boot removed and engine off. Spin the turbocharger compressor wheel with your fingers to make sure it spins freely without any drag. Also make sure it does not contact the housing and is free from any damage. Check your charge air cooler for any leaks as well.I hope you find this information helpful. Reply back with the results of these checks if any further help is needed. It is a pleasure to help anyway I can.