Boost problem???

[atmdoc]

For the past 2-3 months I've noticed while going 60 mph level road, my boost goes from 3# to 0 then back up to 3#. Also my EGT (post turbo) went from 350 to approx 425-450. My mileage also dropped about 3 mpg. Engine starts and runs OK. Can anybody suggest things to check? Thanks in advance.

[rjschoolcraft]

Vacuum leaks or intermittent wastegate solenoid operation would be tops on my list.

[Barry Nave]

Hum :confused: Should see around 5psi. So waste gate is not being able to stay closed even at 60mph.

[atmdoc]

If I go up a slight hill the boost will stay. If I go down a slight hill the boost goes to zero and the engine makes a racket like it's going to come apart.

[Barry Nave]

I would go with RJ then. When you say going up a hill, what boost are you seeing? going down hill there will not be any boost for the Eng. is not under any load. With my truck I lost all boost. Nothing,and I went through the whole system would bring back the boost. Short of R&R the ECM/PCM I just installed the Turbo Master.
My truck remindes me of myself,some things can't be fixed :D

[gvt]

atmdoc,
I'd second the wastegate solenoid, mine failed a few months ago with similar symptoms.

[atmdoc]

To all, thanks for info. I now have a starting point.