FYI, never count on GM's tuning being spot on. There are tolerances that allow the PCM to adapt to the vehicle it's in, conditions driven in, etc, etc.

You and I could take our stock tuned GXP PCM's, pull out all the mapping tables, and I bet there are some level of variance. So I would imagine between years, as GM added on more OBDII capabities, self testing mechanisms, and other provisions in the PCM tunes, there can also be a difference despite having an identical part#.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

just cause they have same part number i dont see why they should have the same stock tune

_________________
Cardomain link

Fully tinted, 5000K HID hi/lo & fogs, LED conversion (interior/red rear signals/reverse light/license plate/trunk/sun visor/glove box/switch backs), turn signal mirrors, JVC KW-NT3 Navi & BT, KV-CM1 Camera, 2x JL 13TW5, JL G-Max, black & chrome emblem, 20" black & red, clear corners, center tail light up, half tinted tail lights, cross drilled rotors, Hawk ceramic pads, and more..

Black GXP. One of a kind. RIP.
G35 Coupe 6MT. Stockishhh

I was concerned when I first got this Bonneville (my first with the N*), as I was averaging about 9 mpg around town the first couple days. But once I got it 'on the open road' I was pleasantly surprised. I'm getting 25 on the highway and averaging about 20 overall during the work week. I have a 17 mile commute for which I usually take a US route rather than the interstate. It's certainly no worse than the GP GXP I had prior.

_________________

2005 Bonneville GXP (SOLD), Crimson Red Tintcoat
Other Rides: 2009 Solstice GXP Coupe #606, Cool (Liquid Silver) | 2007 BMW 750Li, Toledo Blue Metallic
Past Rides: 2007 Grand Prix GXP, Red Jewel Tintcoat | 2004 Grand Prix GT2, Fusion Orange | 2002 Bonneville SSEi, Black | 1999 Regal GS, Black | 1997 Bonneville SSE, Blue-Green
1994 Cutlass Supreme S, Turquoise | 1989 Cutlass Supreme IS, Bright Red | 1988 GMC Sierra 1500, Dark Red | 1982 Regal Sport Coupe, Maroon/Silver | 1975 LeSabre, Beige
Wife's Chariot: 2006 Buick Rainier CXL, Red Jewel Tintcoat

My numbers seem to be falling right in line with everyone else's. Not a car to buy if fuel economy is a priority.

I sure get the feeling that with a sharp tune, this thing would give both better mileage and more power. Oh well.

_________________
2004 GXP - Greystone and stock

95 Oldsmobile 98 L36. 180 degree thermostat. Tru-Cool tranny cooler. Touring Sedan wheels. FE3 springs. Urethane End Links. Magnaflow Cat 94006 -> Soon to be replaced by something that works. WAI. Ported and polished LIM.
Mods coming soon - . Touring Sedan seats. TS Sway bars. - Sold

97 Oldsmobile LSS L67 - Stock. For now. - Sold

It will be interesting to see what the new PCM for the GXP will do to the gas mileage. (And HP/TQ!!!)

_________________
2006 Saab 9-7x 5.3i
2005 Pontiac Bonneville GXP / 4.6L Northstar *Sold*
2001 Olds Aurora 4.0 w/GXP Exhaust and High-flow cat (OSV Wannabe) *Sold*

2001 Pontiac Bonneville SSEi, 3.4" MPS, Intense Tune, SD headers, high-flow Cat, GXP exhaust, Modified Air Intake, 180* thermostat, GXP: 18" GXP wheels w/255/45/18 tires, CF Trim, Brakes and Strut Tower Brace. SOON TO HAVE: GXP Swaybars.

1972 Olds Cutlass Convertible / 461ci Olds / TH400 / 3.08 Posi. 13.62 @ 99.7 MPH......Got torque?


Yes, I seem to be drawn to GM's orphaned cars......