MarineBri68

Thanks, I wouldn't have thought of that with there being so few miles on the car. I'll give it a shot.

Brangeta

MarineBri, I have some suggestions.

If you learn to drive in manual mode, you can get a little better mileage. The automatic mode shifts too damn early on these cars and ruins the gas mileage. Since you are a new owner, you should drive in Drive awhile, and if there aren't any cars around you, watch at what points the car shifts gears by watching the tachometer. (I rarely look at the tachometer and only go by sound, so I'm not sure when it normally shifts.) I think at normal driving behavior, it shifts somewhere around 2000 RPM each time. If that's true, when you are in manual mode, you need to wait until about 2500 RPM to shift out of each gear. You'll know you did it right if the gear change is extremely smooth in manual mode. If it clunks or jars you a bit, you most likely shifted too early (just like the stupid computer does when driving in D). Do not decrease your amount of throttle when shifting, just remain consistent for maximum efficiency. After awhile, you'll be able to easily shift by the sound alone and you'll get smooth gear changes like I do.

I accelerate fairly aggressively as these cars do not make good gas mileage when puttering around like a granny. You need to accelerate a little quicker than the average person's take off from a stoplight. I shift out of first somewhere around 20 or 25 mph I think, out of 2nd around 25-30 if I don't have space because of a car in front of me or at 35 if I have room, and you'll want to stay in 3rd from 25 to 55 mph to take advantage of both DoD and the fuel efficiency of 3rd gear. Only go into 4th if you are done accelerating and are at 50+ mph or if you want to just pop it into 4th and coast to a stop light at any speed over 35mph.

Just for fun purposes, like a highway onramp, just for your own info, you can safely stay in 2nd gear to 90+ mph. If you are going 70... don't downshift to 2nd to accelerate though... you should use 3rd to accelerate or just stay in 4th.

Don't downshift to 1st gear to slow yourself down pretty much... ever. Unless you are going less than 20mph. Just use your brakes or at least a combination of the two. You can use 2nd to slow yourself down from 45 mph without braking on the way to stop lights to save on brakes... but keep in mind you'll need to change your transmission fluid more often (every 40k miles is what I do), and you shouldn't do this if the DIC says the transmission fluid temp is over 180 because you'll heat it up to 210+ quickly.

To easily test if you have DoD still enabled, you'll need to be at about 30 mph+ in D (Drive) and after you stop accelerating, if you lightly let off the gas and feather back onto it, the sound of the car should change if it is going into 4 cylinder mode. The exhaust sound you can hear behind you as you drive should sound a little more similar to a helicopter following you. If you're already comfortable driving in manual mode with the paddles/tapshift, it's even easier to diagnose as the car will only use DoD in 3rd and 4th gear. I purposely feather the throttle like this after getting up to the speed I want so I will immediately go into 4 cylinder mode.

Bob@BruteSpeed

iTrader: (16)

I wouldn't either normally with the low mileage, but since your car is getting such low highway mileage, the 02 sensor may be faulty. Bob

MarineBri68

Thanks for the input. I have tried using the paddle shifters some but only when I was trying to get on it and it didn't work out so well lol. I tried going by the sound like I would with a stick but it want's to shift into second sooner than I thought it should so the rev limiter stopped me I'll try playing with that some. So did ALL the GXP's come with DoD or was it just an option? Also if I decide to change out that front sensor, anyone have a link where I can see exactly where it's located? I have been looking around and can't seem to find what I'm looking for.

On a different note I have been considering getting something to "chip" the car. Wanting to turn off the rev limiter and things like that on demand.....maybe. If I were to do this I know I need to be careful or I could ruin my tranny....thinking about installing a transmission cooler to help with that....but I'm curious what your opinions might be on any cons to doing it and maybe what model/brand system might work best?

Thanks again for the help.

Brangeta

You'll get used to it, it is going to take some time though. For racing purposes, it's actually better to put it in Drive because it won't hit the rev limiter like you will in Manual. D is actually pretty good at full throttle, it just sucks for fuel efficiency and smooth shifts at normal commuting pace.

All GXPs came with DoD. In I think 2007 it was renamed Active Fuel Management, but it's the same thing.

I don't know where the front O2 sensor is located. There's a forum called GPONA or something like that that has some exploded diagrams and parts manual type of deals for our cars I think...?

I don't think there's really any reason to want to go over the rev limiter (as in the "redline") as the torque just isn't really there at higher RPM I don't think. If you're talking about how when you are in Park or Neutral the limiter doesn't let you rev past like 3500 or 4000 RPM, I think that's to protect the motor mounts. You'll likely break the front one sooner or later from horsing around in Manual mode, so you might as well protect it while in Park/Neutral lol.

If you commute more than 20 miles one way, especially in traffic, I would definitely suggest a transmission cooler. I don't have one, but that's only because I don't drive that far, so it's very rare I see a temp over 160 much less 210+. Temps above ~200 start to cook the transmission fluid. I don't know where to get one, just know a bunch of people mount them to the front of the radiator so it gets the coldest air first.

Ill_Born_ss

Can you tell me a little about your abilities
-(mechanical, basic, intermediate, advance)
-do you have any means of viewing live data
-do you have a basic vacuum gauge

fieroguru

iTrader: (1)

There is no front O2 sensor for the LS4. It only uses a single O2 sensor upstream of the cat to control fueling for all 8 cylinders. It is located on the down pipe right after the rear exhaust manifold and before the cat.

Ill_Born_ss

There is actually 2 o2 sensors, both labeled bank 1 (sensor 1 upstream and sensor 2 downstream)

Bank 1 sensor 1 is located in the rear exhaust manifold, if you look with a flashlight down between the firewall and the rear of the engine you will see it. The wiring pigtail for it is attached to the rear coil mount bracket.

Bank 1 sensor 2 is located after the cat.

I do not recommend just changing it without first monitoring it to know for sure. It sounds more like a faulty MAP sensor or a vacuum leak somewhere.