loss of power and surging

[barebackjake]

first starting noticing this on the freeway 75mph, and surging, been happening more and more lately, then today...it was hot today mid 90's. lost power and lots of black smoke, kinda went away at 40 mph then it came alive, but lost power on the top running hills that i normally run at 55-60 barely able to keep it above 40. fueled up this morning, and fuel looked and smelled fine, ran good this morning.
Wastegate?? Turbo?? IP?? then started running better later in the day.

i dont have a boost gauge or egt on it yet.
just dont want to have to go to the stealership if it isnt the IP
97 G3500 102K mi

stock execpt for 3" ex from turbo back 6' and turn out w/ magnaflow

looking at gauges and boost controller but dont know which one

thanks

jake

[tom.mcinerney]

Wastegate solenoid intermittent, varying boost??
See autozone for free code read, use old mech vac/press gage to check vac at pump/sol/wastegate.

[charliepeterson]

Surging on the highway can be fuel starvation. Try opening the water drain "T" valve next to the thermostat with the truck running. If nothing comes out the lift pump is dead. Now it could be a bad oil pressure switch or a bad lift pump or both.

[barebackjake]

thanks guys
ill try that

i put a new fuel and air filter in tonight, haven driven it yet
its a van cutaway chassis so things are a little differnt, the water drain is the bottom of the filter, open it when its running?? right

how much vac should i have at turbo? new vac pump 6 mo ago
no ses light codes have poped up, does that mean there still could be one there though??

[charliepeterson]

put a new fuel and air filter in tonight, haven driven it yet
its a van cutaway chassis so things are a little differnt, the water drain is the bottom of the filter, open it when its running?? right


Yes the truck should be running. I missed the G3500 the first time. This set up IS a little differant than ours. I believe the power to the lift pump is the same. Some of the components are easier to get at too.

[barebackjake]

yeah some easier to get too, some just cant used enough 4 letter words about where they put that, well its better now, its worse with the a/c on, i think it might be a vaccum problem. looking at manual turbo controllers

any suggestions??
concerns?