Maxforce 13 Low Power, will not pull at higher speeds.

There was a thread about injector wires being cut under the valve cover.
I had a tech read my codes but his software could not read any data on the #6 injector. It was just not there.
If I had an injector not working what would my symptoms be? Would the truck still go 75mph.
Would I easily be able to tell the injector was not working or would it be wide open pumping fuel?
I have low power and poor mpg. Power on the low end is OK but it will not pull at higher speeds?
Any input is appreciated.

 

He said there were no codes. he was doing the cut out test and they were all good but it would not show any data on #6. It was not there at all.
The oil is good. Would the truck still go 75-80 mph if an injector was not working? I was thinking about pulling the top and looking at the wires. My knowledge is limited and I don't have the money to just throw at it. It has a new air filter. I will look at the wires at the charge air cooler. I saw a thread saying they have found wires cut under the cover. Thanks for the help.

 

He could not test #6 because his computer did not show that #6 existed. The truck starts up immediately. it has a little rough hesitation when pushing the throttle, it idles fine though. It will get to 40-50mph fine but struggles after that by taking a long time to make speed and it cannot maintain speed going up even a small incline/hill.
I agree, more testing but I like to look for the basic stuff first and I know that sometimes the guys with experience can zero in on things.
Thanks, again.

 

That is very interesting, I wonder what is going on? I don't want to replace the injectors without knowing that it needs them. I was thinking about the high pressure turbo. Maybe removing the cartridge and cleaning it. JB7 has got me thinking about the charge air cooler but you have me wondering about the tuning. I drove another one of these trucks and it did the same thing but maybe worse than mine. They should not have this problem and there has to be a reason.
There must have been something wrong with the software the tech used to look at my truck.

 

Do you get / have a check engine light? Maybe something is telling the system to limit the turbo boost pressure?

 

Or limiting the fuel to the injectors.

 

It this engine doesn't have an IPR or ICP sensor how does it regulate pressure to the injectors?