OK so my 03 Excursion 6.0 was acting funny you could floor it and it would get about 5 psi of boost then in about 5 seconds or so it would take of like it had NOS. I also had an oil leak coming from the back of the top of the engine.

SO I bit the bullet and pulled the turbo off to clean it. I replaced that sensor that is up under the turbo (ECP? whatever the name is with the three wire plug that leaks oil) I think that sensor was the oil leak as it was all covered in oil back there. While I had the turbo off I went ahead and cleaned it with instructions I got on here. It turned out to be a reman unit that must have been put on before I got it but was pretty clean. I cleaned it all up and put it back together. Whoever put the reman unit on messed up and had the gasket for the oil line that goes in the top off center so that the oil passage was about 1/3 blocked. I don't think that was the issue though as it ran great when I first bought the truck and I have put 50K miles on it.

So with the sensor replaced and the turbo cleaned I am still having issues. From a dead stop I floor it, it gets up to about 5psi then after shifting into second it will take off. The most boost I see is 15psi with my tunner on #5.

Any ideas on why it has such low boost then takes off?

 

Could be turbo's VGT solenoid going...or there may be a leaky CAC boot or exhaust up pipe.