My father has a 2001 with 630,000 miles. It is all stock with original injectors. He had been driving around for about a month with a miss. This past weekend we did the injector o-rings, replaced the harness under the valve cover,and installes new valve cover gaskets. Miss is gone and truck is running much better but he is telling me that it is very sluggish on the bottom end and he can,t hear the turbo spooloing up anymore. Any ideas? Should the turbo be rebuilt? Could it be a boost leak?

 

Up pipes, would be a place to look, there will be black soot on the insulation at the fire wall behind turbo, also replace intercooler boots, or check for leaks,that is if none of this as be done.

 

It is most likely a boost leak. Chances are there is a boot loose that you put back in. Search on here for boost leak detector, build one, and then track down the leak.

 

See my gallery pictures for a homemade boost detector..

 

I just wanted to add wow. Thats a pile of miles on a 7.3, thats over a million kms!

 

That is awesome. Quite high mileage for stock injectors so that is impressive as well. We are starting to see new users posting here with 500k-800k miles on their trucks with an issue or two. That tells me there might be a lot more 7.3 owners out there that have racked up a ton of relatively trouble free miles and are now just beginning to have issues and have found this forum. It's pretty cool to hear about high mileage Power Strokes that are still chugging away.

The guys have you on the right track. Sounds like a loose IC boot or possibly leaking up pipes. Check out the turbo for missing bolts while you are looking around. It's not super common but common enough to take a look. I've seen trucks with all 4 bolts missing and there was a huge exhaust leak....but the truck just kept on running as if nothing was wrong.

Here is a pic of the bolts I am talking about. This photo was taken with the turbo on a table but you can still get the idea. There are two bolts visible in this photo but be advised there are also two bolts on the backside that you can't see here. You'll have to use a mirror or check by feel to make sure they are still there. Of course it goes without saying, but be careful if the engine was recently running because the turbo gets hot.