PERFORMANCE · DIAGNOSTICS · TUNING

DR. UNDERHOOD AUTOMOTIVE SPECIALIST

Fixed right the first time — every diagnosis backed by real data, not guesswork.

SERVING: Fort Smith AR · Van Buren AR · Northwest Arkansas · River Valley · Eastern Oklahoma
CALL NOW GET A FREE QUOTE
5300 Towson Ave, Fort Smith, ARMon-Fri 8AM-5PM, Closed Sat/Sun
DATA-BACKED DIAGNOSTICS
datalogs, not guesses
HP TUNERS CERTIFIED GEAR
real dyno-verified tuning
AUTHORIZED JASPER INSTALLER
3yr/100k nationwide warranty
EVERY FIX ON RECORD
your vehicle's history saved

WHAT WE DO //

HP Tuners ECM/TCM Custom Tuning (GM V8 Trucks)
AFM/DOD Delete Cam Tunes (GM 5.3 / 6.0 / 6.2 V8)
Cam Swap Tunes (Cam Motion, Comp Cams, BTR)
Knock-Verified Spark Tables & VE Table Tuning
Datalog Diagnostics & Drivability Repair
OBD-II Diagnostics
Brake / Suspension / Electrical Service
Engine Work & Performance Repair
AI-Powered Pattern-Matched Diagnostics
Pre-Purchase Inspection
Maintenance & Tune-Ups
Authorized JASPER Engines & Transmissions Installer & Dealer (3-year / 100,000-mile nationwide warranty on JASPER reman gas engines, transmissions, marine, differentials)

SPECIALTIES //

WHAT WE'RE KNOWN FOR

AFM/DOD Delete TuningGM 5.3 / 6.0 / 6.2 V8 Cam TunesHP Tuners Master-Certified TunerKnock-Verified Spark TablesDatalog-Backed Tunes (Not Flash-and-Pray)JASPER Reman Engine & Transmission Installs

EVERY FIX REMEMBERED //

We log every job into our shop's AI brain. Next time something similar rolls in, we already know what fixed it.

That's how you stop paying for "let's try this" diagnostics. Doc Underhood gets your truck right the first time.

REAL TUNING //

HP Tuners. Datalog-backed. Verified on the dyno. Not a flash-and-pray operation.

AFM/DOD delete, cam tunes, diesel performance — done with knock data, AFR traces, and a write-up of exactly what changed.

We Install
JASPER
Engines & Transmissions
3 Years / 100,000 Miles
Parts & Labor
Nationwide Warranty!

AUTHORIZED JASPER INSTALLER & DEALER

Reman gas engines, transmissions, marine, & differentials — backed by Jasper's 3 Year / 100,000 Mile nationwide warranty. Installed right by Dr. Underhood, warranted everywhere.

Visit JasperEngines.com

GET A QUOTE //

SHOOT US YOUR VIN OR WHAT'S GOING WRONG. NO BOTS. NO ROBOCALLS.

DOC READS EVERY ONE — MOST GET A CALLBACK SAME DAY.

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