This is been an on going problem . Lots of power on the bottom end then falls on its face. Tried two strokeoil yesterday but still the same. . Could it be the map sensor ? . Check engine light has been on for a while now . I can hear the turbo spoiling up but no power. Also the transmission is always hunting while unloaded but while towing it stays in high gear. At s loss here . Any suggestions ?

 

What year is the truck?
Any black smoke when it lays down?
What wastegate control do you have?
Vac pump if equipped good-24"+ vacuum?
Vac lines leaking/cracked?

These engines with the stock turbo fall on their face after 2400rpm's-fact of life.

To get better high rpm performance get an ATT tubo or mod a T3 flange Holset HX40 to fit.

Find out what codes the truck has first and foremost-no crystal ball here to tell you if the map is bad.

 

The truck is a 98. There is tons of smoke when I put my foot in it. I'm not sure about the vac pump. Problem is a while ago I changed the drive belt and put it on incorrecty and had the pump spinning in reverse. I don't know if it was hurt but seems to be operating ok now. The engine starts loosing power at about 1800 . I think I'll have to see how much vacc I have this weekend.

 

Ok from the wastegate solenoid on the drivers side valve cover you should have 24"= vacuum from the vac pump line(orange) and 18"+ from the other port-same at the wastegate actuator on the turbo.

The wastegate solenoids fail and sometimes can be brought back by a shot of wd40 in the vac ports(possible code?).

 

Ok just finished checking . I have 28" at the pump and 16" at the turbo. I took it for a drive with the trailer and still a dog on the top end . Great power on the bottom end . The transmission goes into limp home mode and boosts the line pressure but stays in high gear on the highway. Dropped the trailer and still hunting with the lock converter. Lots of smoke if I put my foot in it . The exhaust is changing tone in the level ground so I would say the waste gate is working . fine . I'm going to drain the tank tomorrow and go back to straight deisel tomorow.

 

Give the wastegate solenoid a shot of wd40 through the vac ports-the vacuum to the actuator should be much better when the pump produces vacuum like that.

Also check the vac lines for cracks.

 

Tried the ad40 and worked like a charm . Power is back and cured the transmission hunting. I'll check the milage this week . Thanks to racer55