Fuel map = talking about computer file on your car ECU that handles fuel delivery to the engine. Can be adjusted with ECU tuning equipment (improve performance, accommodate modifications).
Nasty hole = not a set term but from context I understand it to mean there’s a poor adjustment he made to the Fuel Map that is resulting in power loss
Unloading = not a set term but most likely referring to Engline Load (capacity to produce power) so from context, the car is losing power in third gear
Third = third gear on the car. Very common to refer to gears as just numbers. E.g. “the car was still spinning its tires through third”
Lengthened Injector pulse = from context he’s talking about adjusting/tuning certain parts of the fuel map (injectors refers to fuel injectors). Injector pulse is a super technical term referring to the length of time in milliseconds the fuel injector is working. Car guy know/what it means/even I had to Google the term
Tune the NOS timer = make adjustments to the part of the Nitrous Oxide system that times when Nitrous is sprayed into the engine (presumably to accommodate changes in when the fuel is delivered to engine)
You’ll run nines = saying that with these adjustments to the ECU and making changes to your Nitrous system, you will run a nine second quarter-mile finish time in drag racing.
(9’s were a very impressive time in that early 2000’s era that could only be accomplished with heavy modifications on certain cars costing tens of thousands of dollars. Stock Ferraris 360 Modenas of that period ran the quarter mile in mid 12 seconds by comparison. Nowadays cars are much faster: you can buy a dodge demon from a dealership that runs mid-9’s stock, and the Tesla Plaid is into the low 9’s almost breaking 8’s. Modified drag cars are also much quicker these days with several thousand horsepower no longer rare or unheard of and batshit quartermile times (think 5’s and 6’s)).
Anyway, this movie (original Fast and Furious) was famous for using car jargon often just because it sounded cool and in ways that weren’t technically accurate and interspersing fake brands and made up terminology that car people cringed over. This exchange was passable although incredibly technical.
I know this reply is to an ancient post, I just love this movie so much 😅