Hey everyone,

I am now an owner of a 2004 Buick Lesabre, and have been looking for something in the 3800 series to turn into a sleeker. While the h-body is not typically a very “moddable” platform, there are enough resources & reliable aftermarket options out there now to put it up in the running for a fun yet discreet street car.

I’ll be posting updates in this thread as much as possible, I plan on doing a few different steps or stages if you will

- Initial inspection / routine maintenance
-engine / transmission
-suspension
-interior / exterior

- Max out N/A & preparation for boost
- PCM & Tuning
- Fuel & Ignition
- Drivetrain

-Supercharger conversion
- Stock motor max out
- Begin Built motor (turbocharged)
- Custom Modifications







Initial inspection

I purchased this Lesabre for 3k cash, the first drive brought out some random misfires which I attributed to poor maintenance at the time.
After getting her home I did an oil change, replaced spark plugs & wires, removed & cleaned coil packs & module, removed the snap ring & mesh screen in the throttle body pre MAF (something shot through the intake, there was no filter, and ripped the mesh screen).

After that I was still getting a misfire, and it showed a pre-cat Oxygen sensor issue. Replaced that, and we continued to misfire. Checking again narrowed it down to a cylinder 1 misfire - checked gap (.056) on replacement NGK TR55, plug wire connections, and coil pack connection. Issue was resolved under normal driving conditions, but when under high acceleration I got yet another code. P0420 linked to catalytic converter issues. The converter will be replaced temporarily and soon I will be ordering a downpipe - resonator system from ZZP, along with their stage 1 PCM.

will post some pictures when I get home! Phones about to die haha