Hey guys,

I have owned a 2003 SLE for about 6 years now, and really like it! The mileage on it is getting up there, and I am considering buying a 2004 GXP with about 75000 miles on it.

I am wondering about the gas mileage on the V8 powered GXP. Is it going to be about the same as the 3.8L? Most times I do not have a heavy foot, [especially if my wife is in the car too ] Are there any other significant differences in the two cars I should be aware of?

Thanks!

No, it won't get anywhere near the mileage.

Siginificant changes are engine, transmission, factory suspension lowering, bigger wheels, different front brakes, just to name a few of the mechanical things. THen obviously aesthetic things, starting with the front bumper cover.

Figure you have about 25k of fairly trouble free mileage before it starts becoming "needy". Couple that neediness and a size 10 engine in a size 5 dress, and one can see how quickly the honeymoon ends. If you do your own work, expect it to take more time and be more difficult. If you pay someone to do it, expect that they will charge you more for the increased level of labor.

Search this forum, in particular this section. This question gets asked about 2x a week it seems.

_________________


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

Thanks for your reply. I read through a few other similar threads. It would seem the GXPs are not without their issues as well. I have done just about every repair needed on my SLE myself. New upper and lower intake, rear shocks, front engine mount, heated seat repair, and a few other things. It now needs new tires again, and headlights, [original ones are not repairable] and I'm trying to decide whether to spend more money on it, or sell it and get something else. Not an easy decision... I wish GM still made them! :(

Just spend on what you got. If you had found a pretty clean, low mileage GXP, different story. But it seems as though the things you listed needing repairing on the SLE are pretty minor and in the long run, cheaper. The attraction to the GXP is obviously the 8-holer and it's accompanying running gear, but it too, comes at a price.

_________________


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

I get only 20-21 on the highway with my 04 GXP and it came with only 32,000 miles. I had a 2002 SSEi that would get 25. The GXP will run on regular. I agree with CMNTMXR57 comments. The major issues are gaskets leaking oil and anti-freeze leaks from gaskets and engine plugs. Look the car over well for these, especially after driving it and the engine is hot. Make sure the first thing you do is change the coolant. Minor anti freeze leaks can be handled with GM pellets. You have a lot less room under the hood to work on things. The fog lamps can be a problem (see the sticky thread in this topic). Other than that, most of the other problems are similar to any other 2000-05 Bonneville. The tranny is solid, the 4T80E is the strongest FWD tranny GM ever made. You cant do much to mod the drivetrain for more power. I focused on infotainment and putting in a good sound system with subs. For a 75,000 mile car you should be paying no more than $8,000. And I think the engines can go well over 100k if they were well maintained. But that are not as solid as the 3800 that can potentially go 300K. You will notice it runs at higher RPM than the SLE at highway speeds. Due to the lack of low RPM torque it has 3.71 gears. Look for rusty brake lines and rust under the fuel door on the quarter panel. If that area is starting to bubble, expect to pay $500-750 or more to get it fixed right. Check the carpets for signs of leaks if it has the sunroof, and check the spare tire well to make sure it is not full of water.

_________________
bobgto65

2004 Bonneville GXP 62,000 miles purchased 04/13
2009 G8 GXP PBM, M6 9580 miles, no mods, sold 08/15
2009 G8 GT SBM 36,000 miles, modded 430 whp
2002 Bonneville SSEi 203,200 miles (sold 3/2014)

The seller is willing to let it go for $3K, which is why it made it so tempting. However there is rust coming through on both front fenders, on the trunk lid, and around the fuel door. I can only imagine the rust elsewhere, especially underneath. I have had my 2003 SLE sprayed with Krown every year, and it is in much better condition, even though it has twice the mileage on it. I have pretty much decided to pass on it... I hate rusty vehicles, and there is no way to stop it in its tracks now.

Probably a wise decision. If the body was that rough, I imagine the hood has never been opened unless absolutely necessary.

_________________


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

agree - the rust is a deal breaker. Too bad as the price is great.

_________________
bobgto65

2004 Bonneville GXP 62,000 miles purchased 04/13
2009 G8 GXP PBM, M6 9580 miles, no mods, sold 08/15
2009 G8 GT SBM 36,000 miles, modded 430 whp
2002 Bonneville SSEi 203,200 miles (sold 3/2014)