I have a 98 with 6.5l turbo and I have noticed lately when I am on the interstate it feels like the turbo is being bypassed. At about 70mph the turbo will spool up real fast then die then sppol up and die this will happen 4-5 times in about 15-30 seconds. When I step on it just feels like the turbo is not there. I did check the wast gate and it is not stuck and moves freely. The vacuum pump is working at and idle at least and easily works the wastgate. Is the a map sensor that is acting up or at higher rpms does the vacuum pump start to fall off? Any advise guys?
Travis

 

wastegate system on these trucks is pretty bad and unreliable. have you checked the wastegate solenoid?

 

Yes I checked the vacuum solenoid on the turbo. It holds vacuum at any point along the stroke of the solenoid

 

Get up with Heath and get a tubomaster. Everyone I've talked to has boasted about the improvement it's made on their turbo.

 

A Turbomaster will help, but you'll also need a tune to run it.

Sometimes you can squirt WD40 into the wastegate solenoid and get them to work better. It is a sketchy system. If the turbo dies, there are better options.

 

so would you remove both lines at the solenoid and squirt wd40 into the solenoid itself?
what about the lines?