"Scooter has informed you that you won't be able to reach Moxxi unless you have a vehicle. Scooter has been working on a new set of wheels but needs you to grab the last few parts needed to finish the boost system. Search T-Bone Junction for the needed parts."
Collect the necessary parts to complete the new vehicle
The vehicle parts are denoted by way points around T-Bone Junction. The exhaust pipe can be found in the crashed vehicle outside Dr. Zed's clinic at the topmost level. The nitrous tank is found among the garbage of the empty lot in front of Marcus Kincaid's place. The supercharger is found among the hanging rooms below the nitrous tank's location.
"You've found all the parts for Scooter's new car. Sounds like he wants help installing them now."
Near the location of the nitrous tank is an ambush point where a squad of Lance Assassins appear. This ambush starts the mission Wanted: Dead!.
The Lance assassins may not show up while getting the Nitrous tank during the mission.
Text of Mission items:
X-372 Supercharger: Thankfully, this is not the X-373.
Nitrous Oxide Tank: The nitrous tank Scooter needs.
Exhaust Pipe: The exhaust whatcha-ma-doohicky for Scooter's new vehicle.
You ain't gettin' nowhere without wheels boy... and maybe girl. I've been cookin' up somethin' new but I ain't finished the booster system yet. Need a bit'a secret sauce if you're willin' to lend a hand.
Alright! What I'm gonna need is a X-372 Supercharger, but not the 373... there was a recall on that thing on account a people burning alive. Also, a big 'ole tank of nitrous, and one of them fancy exhaust booger things. I don't even know what it does, man.
(Upon finding the supercharger)
Smokin' Jesus titty cinnamon! That is a monster! That's gonna be sweet!
(Upon finding the nitrous tank)
Well, shoot, looks like the passenger seat's gonna have to go bye-bye to fit that bad boy in there. I'll get to work on that right now.
(Upon finding the exhaust pipe)
Yeah... Yeah, that's probaby the thing that... does the other thing... and shit.
(Will be the last message, replacing the quote of the last part found.)
I could always tell you were the resourceful type. Bring 'em on back and we'll get you rollin'!