Catalytic Converter for GMC Sonoma (1996-1999) 2.2L Rear

Direct-Fit Rear Catalytic Converter for 1996-1999 GMC Sonoma (GMT325)

What it Does: The rear catalytic converter replaces the degraded downstream catalyst assembly on the 1996-1999 GMC Sonoma 2.2L to clear OBD-II catalyst efficiency trouble codes, eliminate exhaust backpressure, and restore emissions compliance.

The Stock GMC Sonoma Substrate Degradation

The factory catalytic converter on the second-generation GMT325 Sonoma frequently suffers from thermal fatigue and substrate breakdown over high mileage cycles. The aging ceramic monolith in the factory LN2 (Vortec 2200) exhaust stream experiences washcoat sintering and physical wash-out, resulting in persistent P0420 efficiency codes. Furthermore, structural collapse or carbon glazing inside the original converter core chokes exhaust scavenging, generating excessive backpressure that causes rough idle, elevated cylinder head temperatures, and noticeable top-end power loss.

The Engineering Solution

This replacement converter is fabricated using a heavy-gauge 409 stainless steel housing designed to resist road-salt corrosion and mechanical stress. Inside, a high-cell-density 600 CPSI cordierite ceramic substrate is loaded with a high-activity washcoat of palladium and rhodium precious metals to maximize chemical conversion efficiency of hydrocarbons, CO, and NOx. Smooth mandrel-bent inlet and outlet tubing preserves laminar exhaust gas velocity, while precision-machined flanges mate cleanly to the factory exhaust layout. Factory-located O2 sensor bungs allow factory downstream sensors to thread directly in without wiring harness modifications or bung extensions.

What's Included

• 1 Catalytic Converter (Rear)
• Mounting hardware

Technical Specifications

Compatibility

• 1996-1999 GMC Sonoma 2.2L L4 (Gasoline)

Frequently Asked Questions & Fitment Warnings

Does this fit the GMT325 Sonoma?

Yes, this is a direct fit for the 1996-1999 GMC Sonoma equipped with the LN2 2.2L inline-four; this unit is not legal for sale, purchase, or operation in California, Colorado, New York, or Maine, and does not fit 4.3L V6 models.

Is welding or pipe cutting required for installation?

No, this unit is engineered as a true bolt-on direct replacement using OEM-spec flanges and included mounting hardware.

The GMC Workhorse Standard

Maintain your compact truck's daily hauling reliability and smooth drivability by restoring factory exhaust flow velocity and clean emissions operation.