GM made two costly engineering compromises that affect nearly every LS/LT V8 truck and SUV:

• AFM/DOD cylinder deactivation — GM's fuel-saving system shuts off 4 cylinders under light load, but the lifter mechanism is prone to catastrophic failure
• TCC slip strategy — To mask AFM vibrations, GM engineers intentionally allowed the torque converter clutch to slip ~60 RPM. This overheats and wears the TCC over time, causing shudder, poor driveability, and eventually complete transmission failure

A custom tune fixes both:

• AFM/DOD permanently disabled — engine lasts longer
• TCC apply strategy recalibrated — shudder eliminated, converter protected
• Shift points and shift feel improved — more responsive, less laggy

Most shudder and rough shifting issues can be resolved with a tune alone — as long as there are no major underlying mechanical issues.

A custom calibration optimizes your vehicle's fuel delivery, ignition timing, shift strategy, and torque converter behavior for your specific engine and driving style. You can expect improved throttle response, stronger and more consistent shifts, elimination of torque converter shudder, and longer transmission life. Most customers notice an immediate difference in drivability.

Requirement: Windows 10 or Windows 11 laptop — the HP Tuners software is Windows-only and required to communicate with the MPVI device.

Once you place your order:

• You'll receive detailed instructions for pulling your factory tune file using the HP Tuners MPVI device
• Email the tune file to NewhookTuning@Gmail.com
• We build your custom calibration and email it back within 1–2 business days
• You flash the new tune to your vehicle using the MPVI device
• Drive and test — if any adjustments are needed, send a new datalog and we'll revise

HP Tuners is the industry-standard software and hardware platform used to read and write calibration files to GM ECMs and TCMs. The MPVI is a hardware interface that connects your laptop to your vehicle's OBD2 port. HP Tuners uses a credit system to "unlock" vehicles — credits are purchased directly from HP Tuners at hptuners.com and are not collected by Newhook Tuning.

We ship you a ready-to-use MPVI4 device. Rental is $100/week, plus a $450 fully-refundable security deposit. The rental period starts when the device ships and ends when we receive it back. If you exceed your rental period, $15/day ($100/week) is deducted from your deposit refund. Most customers complete the process in a week. Return shipping is on you via any carrier.

For stock or mildly modified vehicles, no. We work within safe, known parameters using factory sensors and datalog feedback. For heavily modified vehicles (aggressive cam, forced induction, large injectors), a wideband O2 sensor allows us to verify air/fuel ratios precisely and push the calibration further safely. We'll ask about this in your order form.

We specialize in GM LS/LT V8 engines and GM automatic transmissions (4L60E, 4L65E, 4L80E, 6L80, 6L90, 8L90, 8L45, 10L80, 10L90). However, if your vehicle appears on the HP Tuners supported vehicle list, we can likely tune it — GM or not. Reach out and ask.

Active Fuel Management (AFM) and Displacement on Demand (DOD) are GM's cylinder deactivation systems, designed to save fuel by shutting off 4 of 8 cylinders at light throttle. While fuel-efficient, the lifter mechanism that enables this feature is prone to failure, often causing catastrophic engine damage. A tune can permanently disable this system in software, eliminating the risk entirely without any hardware removal.

Technically, modifying vehicle software can give a dealer grounds to deny warranty claims on affected systems. If your vehicle is still under factory warranty, consider that carefully. For vehicles out of warranty, this is generally not a concern. All tune files can be reverted to stock if needed.

If you have issues post-tune, first send a datalog — most drivability concerns are resolved through the included or additional adjustment sessions. If a mechanical issue is present, no tune will fix it. We'll always be honest with you about whether a problem is software or hardware related.