Paul Walker Death -- Porsche's Been Sued Before Over Deadly Carrera GT

Paul Walker wasn't the first to allegedly experience mechanical issues inside a Porsche Carrera GT -- TMZ has learned, the car company was sued over a deadly 2005 crash involving the same vehicle ... and it paid dearly in a massive settlement.

According to the lawsuit, two men (a driver and his passenger) were killed on a California race track while driving a 2005 Carrera GT ... hitting a wall at over 100 MPH while trying to avoid another car on the track.

The family of the passenger sued practically everyone involved in the accident for gross negligence -- and won $4.5 million in a giant settlement ... $350,000 of which was paid by Porsche.

The lawsuit alleged the GT didn't handle correctly on the track -- and according to the attorney for the victim's family, Craig McClellan ... sworn testimony from several Porsche experts confirmed a major design flaw with the GT is it doesn't have a Porsche Stability Management system.

We're told the PSMS uses a computer to correct the car if the rear end loses control -- and it is now required by law.

For Porsche's part, the company denied liability -- saying the car fully met federal safety standards at the time -- but it still paid its portion of the settlement to avoid further litigation.

It's unclear if Roger Rodas' Carrera GT had been fitted with a PSMS -- but McClellan says ZERO 2005 Carrera GTs (like Roger's) came off the assembly line with the system.

PSMS or not, it's worth noting the car has been a HUGE legal pain in the ass for Porsche. So far, Paul's family hasn't filed a lawsuit.