ls1 performance edit

[Macka21]

Hi i have a performance ls1 edit and a mafless tune and my car is running crap like makes a noise like a rock has hit the under carriage of the car. Could this have anything to do with the noise im hearing

[ucwepn]

Is it a loud clunk when you are slowing down? could be a driveshaft, could even be something else in the drivetrain.

[Macka21]

Yeah and u feel it in the foot well and its while ur driving

[HSVSENATORVY]

it could be the rubber cuppling between the box and shaft might be split or broken thats what is was in mine any way

[Not_An_Abba_Fan]

Has it got the stock cats still? They break up and rattle.

[macka_21]

yeah still stock cats
its also missing could the mafless and ls1 edit be conflicting

[Munz]

no way - the tune would have nothing to do with it > as you say you hear it coming from under your car

Does it make the vibration/noise all the time or intermittently?
" " make more vibration/noise when car is revved harder or more on deceleration
have you pulled your cats of to check?

[Macka21]

Its intermittent and just when im cruising and when i take of from a corner its sluggish like it wants to die and its running rich and using more fuel then normal like 22l per 100km

[Macka21]

How would it be my cats if they were broken it would be making the noise all the time? not intermittent would it