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04 Grand Prix GTP

Gunner0812

Gunner0812

A(ACLU) Agent Mini Gunner
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Dayton, Oh.
Who also has a 04 GTP? The plugs need changed and wondering what plugs would be best to use. The mpg is droping fast right now its 15.2! :yikes::puke:
 
I had a 2000 GTP. I wouldnt change the plugs just yet. I would change the fuel filter first. Its probably the most commonly overlooked piece of maintenance on any vehicle.

Is the air box stock? Have you checked the air filter? If your mileage is dropping fast, do you have a CEL? I ask because it only takes 1 O2 sensor to throw the entire engine outta wack.
 
I'm with Unit...................how many miles?? Plugs should go an easy 100k, and I'd replace them with whatever came stock. Air filters can definately do it too. As far as fuel filters go, I really agree with that one. No one changes them. They all need to be designed like our diesels and easily accessible. Nothing's worse than froze/rusty fittings/lines, then once you break them, or break them loose, you are swimming in gas up to your arm pits!
 
I think they take a special plug. Irradium or something? Did you call the auto parts storea dn see what the choices are?
 
Yea they use Iridium plugs, kinda expensive, but they should only need changing every 100,000 miles. If your over 100,000 I would do plugs, wires, fuel filter, and air filter. I've got a '00 GTP and I'm about to do this myself.
 
I got the GTP from Carmax and so far I replaced the air filter with Air Hog and Mobile 1 oil is in it. Carmax likes to use cheap stuff in the cars and I think they put autolite plugs in the engine instead. I will be changing out the fuel filter and checking the S/C fluid also. How do you remove the plastic cover? I just dont want to break it. Thanks for the help.
 
How many miles are on it? There's no reason they should've changed plugs out already...Unless its got over 100k. Hell, my Ford 4.6 lasted me 119k before one finally cracked so I replaced them all.

Were they still using the 3800 series II or was it series III in 2004? 3.8 with the Eaton blower IIRC.

You want some extra power? Change that 3.9" blower pulley out for a 3.2" or a 3.0" and you'll gain around 5 psi for the 3.2 and 6 for the 3.0. It'll make a NOTICEABLE difference in neck snapping acceleration. Those really are fast cars...And with the smaller pulley, its still capable of 30 mph believe it or not.
 
Unit453 said:
How many miles are on it? There's no reason they should've changed plugs out already...Unless its got over 100k. Hell, my Ford 4.6 lasted me 119k before one finally cracked so I replaced them all.

Were they still using the 3800 series II or was it series III in 2004? 3.8 with the Eaton blower IIRC.

You want some extra power? Change that 3.9" blower pulley out for a 3.2" or a 3.0" and you'll gain around 5 psi for the 3.2 and 6 for the 3.0. It'll make a NOTICEABLE difference in neck snapping acceleration. Those really are fast cars...And with the smaller pulley, its still capable of 30 mph believe it or not.
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Nick its Series III. The mileage is 43,000. I just like to know why the mileage is dropping like a rock! Its never been above 20 mph and dropped since I bought it. Could it be the wires?
 
Fuel filter...Its probably clogged...How does it run? Is it strong when you get in it? You might have a bad cat...They can and will get clogged...
 
I'd get that fuel filter changed asap. Clogged cats also have that feel too. Ive driven/beat on my share of GM 3800 series II police packages and when it feels like it has no power, its either the fuel filter or the cat is clogged and it cant breathe. Id say especially one of those two since you dont have an engine light.
 
x2 on the fuel filter, i put PB on it a day or two before we changed it, might be bad for the rubber seals, but at least it came off real easy and no line bending/breakage. it was full of cruddy looking fuel. i did feel a bit more power on the butt dyno, especially when merging onto the freeway. Air filter may've done it too, as it was changed at the same time. just good maintenance to do it, filters and oil are cheap, gas and powertrain components are not.

I would also think about the plugs, and wires too.
 
Got the Supercharger fluid today. Hall Pontiac didnt have it and told me that it would cost $45.00. Got it a RK Chevy for $10.65!
 
Gunner0812 said:
Got the Supercharger fluid today. Hall Pontiac didnt have it and told me that it would cost $45.00. Got it a RK Chevy for $10.65!
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Think it was $8 or so my cost and it takes a little more then one bottle, I did mine last month. The way I did it was take a spray bottle, like a windex bottle or somethin, stick the sprayer tube down into the fill hole and pump it out into a bottle. This stuff smells really bad.
 
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