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Discussion Starter #1 (Edited)
I'm having problems with the truck surging on moderate acceleration. It drives normal under lite acceleration. It seems to do it only when it warms up. The IAT temp's are in the 90's with the liquid intercooler. It does have a newly installed rear turbo system. I had a dyno tune done and the tuner said it looked dirty all over. Stock it made 212rwhp then with 6 lbs boost it made 340. But with 9 lbs it made 390. Not much of a difference. Did a pressure test on the piping and it's holding good pressure. It should have made a lot more power with 9 lbs boost. It also has 60 lb injectors. Any ideas?
 

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what motor I4 or i5 ? try the forced induction page his name is Cory
 

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Are you logging data that shows your IATs? If so you should also be able to monitor your fuel trims and timing. Sound like either timing fluctuating or fuel trims constantly overcompensating at part throttle. Do you have a wideband hooked up? MAF tune or SD tune? Lotsa stuff comes into play with turbo tune!
 

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Damm, i thought it was an I5 with only 212 hp stock. all the 5.3's i've seen
make around 240 +/- a few rwhp
 

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tinja nurtles
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If it does it after it warms up it sounds like it's fuel trims. Once it goes closed loop it's all over the place I bet. That's the problem with dyno tune shops. The tune for wide ass open and stick you with drivability issues. I get drive ability down before I enter into positive pressures.
 

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Tim, take a ride and go see Cory, he can fix your prob
 
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