speef

Good morning all,

I’m picking up a shake under heavy torque load starting at about 60mph going up to triple digits, doesn’t happen under light acceleration, only when you stress it more, doesn’t happen under constant speed either. So I am inclined to reject wheel balance (there’s no steering shake), feels more like a full chassis shake. I’m thinking CV joints, engine mounts, possibly tranny, shaft balance? I even thought about engine mapping maybe off and causing misfires ? Car has a COBB tune. No idea, need a bit of direction please, not sure where to start. Thank you

aft86

This could be anything from a bad wheel bearing to tires to electronic firmware to tranny or mechanical issue. Someone on a Porsche Facebook group posted about this on his 991 TT and it turned out to be his tires. He replaced, aligned and balanced, and the vibration went away. Before spending any money, I would start with just raising the car and checking each corner, then checking anything on ecu with OBD reader.

speef

Roger that - thank you - I’ve checked tires, but will proceed as you suggest with rest

FAADXB

hi did you ever get to the root cause of this issue? I feel the same thing - very direct/distinguishable vibration on moderate to heavy throttle at 90kph (close to 60mph), leveling off into remote/non identifiable vibration past 105kph. The fact that it is tied to wheel/vehicle speed makes me think it is related to suspension, bearing, driveshaft or tires. The vibration is much less noticeable in sport or sport + modes but still there. It is also faintly present under deceleration at the speeds mentioned above. I have tested acceleration in different gears, boost pressures, and also different awd ratios…but the vibration is still there. The fact that the vibration is strongest during load is also puzzling. Any advice would go a long way. Thanks