Out of ideas

[Scorpiotension]

04 f350, 136k miles. I started having power, cranking, etc problems so had it diagnosed....the infamous 299 code popped up. Long story short.....cleaned VGT, EGR delete, new fluids and filters , ran thru relearn steps.......now, easy start, smooth idle, no exhaust smoke but turbo makes hissing sound and no lower end boost.........someone help, I am out of ideas!!!

[naraptor]

Dumb question but did you check all your boost hoses, intercooler, etc. Note check while trying to make boost.

[PSDMikeB]

Sounds like a clamp on the exhuast is leaking. It can be difficult to get them lined up properly. Do not use the clamps to draw the pipe to the turbine.

Loosen the up-pipe to manifold bolts, loosen turbo mount bolts, be sure to get the pipes lined up flush and square to the turbo, tighten the clamps, then tightn the exhaust to up-pipe connection, then tighten down the turbo mount bolts.

MikeB

[MyTractorsSexy]

id say boost leak but you claim to have upper end power. so maybe increased turbo lag.... maybe you have a smaller boost leak or filter clogged up a bit. maybe at first it receives to much air so the trucks computer cuts the power due to mass air flow sensor. maybe even check the intake tubes from filter to turbo. also do the other steps the others posted

[Scorpiotension]

Thanks guys. Turns out the Y- tube and the turbo were not matched up. A little knuckle busting and bingo, all is now well. After the fix it coughed and sputtered but I took it out on the highway and put the hammer down. I cleared up and is running like a new one. Again, thanks for the great advice.

Mike

[Scorpiotension]

Update: put it on the road yesterday. It drove like new, no lag, no smoke, no coughing, etc. took it out an hour ago.....we are back at it!! Started off coughing and puffin smokebthennit seemed to clear up. A couple more miles down the road it begins to lose some boost, begins coughing and puffing smoke.

Yesterday I was at Autozone, they checked the codes and it showed " no codes ".

I'm at a loss as to what to do next. Need help!

Thanks

[naraptor]

You need a High powered scan tool ( snap-on ) to see live feed, look at your VGT %, boost,etc. We've had seen similar problems with the turbo vanes either rusted up and frozen in place or just destroyed causing no boost then over fueling. You can diagonse the problem with a good scan tool instead of wasting time and money pulling parts and guessing.

[Scorpiotension]

It went to the shop today to find out the issue(s). I hate for a piece of machinery to defeat me.....aaaaaargh!!! I'll post the findings.