Ex-NFL Star Jamal Lewis -- War Over My Pimped Out $350k Super Truck

Lessons In Bad Math -- ex-NFL superstar Jamal Lewis once spent $200,000 to pimp out a Ford super-truck that he bought for $150,000. But wait, it gets worse ...

He eventually lost the car because he couldn't afford to pay the bills ... this according to court docs obtained by TMZ Sports.

The former Baltimore Ravens running back -- who famously went bankrupt after his NFL career -- is in the middle of a legal war over his old 2005 Ford F-650 XUV mega-truck.

Here's the story ... back in 2011, Lewis needed a loan for $35k ... and put up his truck as collateral. But when the time came to pay back the money, Jamal was $10k short.

So the lender SOLD THE TRUCK to recoup the $10k.

Problem is ... Jamal says the truck was worth WAYYY more than that ... and now the trustee in his bankruptcy case is demanding the rest of money from the sale of the truck.

Jamal says he has no idea where the truck is now, but the trustee wants at least $140k from the lender to make things right.