CPU Cut In Horsepower? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

mrtoad3 · 02-21-2014, 01:26 PM

I have an '03 Boxster S with a slow leak in one of the rear tires. When it gets down around 25psi the car feels as if its lost 30% of its power. Pump it back up to 36psi and it feels normal but not immediately.

The only explanation I could come up with is that the car thinks its on ice or in mud because one wheel now has a smaller radius and rotates faster. I don't have a manual for it so does anyone know if these cars had such a thing?

rick3000 · 02-21-2014, 02:14 PM

If you have a 'TC Off' or 'PSM' Button on the dash you have traction control. I am not sure it would affect the performance that drastically.

I think your problem is that you are running one of your tires -10psi from where it should be which will affect all kinds of things like mpg, speed, stability, etc. Repair or replace the tire.

stephen wilson · 02-21-2014, 02:48 PM

It doesn't take much of a diameter difference for the PSM to kick in. Fix that tire !

Davev · 02-21-2014, 04:26 PM

I had a 2006 Mercedes and my wife had a slow tire leak. She rolled into a tire center- they put on a new tire. Same brand. Shortly after that she reported the car was not running right- she would start to pass someone and the power would drop off.

After this went on for a while - I took the car and it was crazy- any acceleration and bingo- power drop. We took it into the dealer- after a few hours they found the tire size was off by one size down. Easy fix.

So fix it