Accelerating after gas & MPG mod question

Hi,

 

I've noticed that in first gear my manual 05 GT will continue to accelerate for about a second after I've let off the gas now and then. Specifically, this happens when I'm starting from a dead stop and let the gas off before I've hit 10 MPH or so. I've never had a turbo car before so I assumed maybe it is that... is this normal?

 

Also, I'm completely stock right now but am about to start adding bits at a time. If anyone has modified any of the following, I'd really like to know how it affected your highway gas mileage as I don't spend much time driving in the city.

 

Intake

(drop in or other filter)

Exhaust

Cobb AP

Anything else that had a noticeable effect positive or negative?

 

I really appreciate any info. Thanks to everyone who contributes on here, I learn a lot just reading your old posts.

106,000+ miles, I haven't noticed what your talking about.

 

I have a Parin filter and Cobb AP stage 1 93 octane. I average 22-23 mpg around town and can get 27-28 at 68-70mph on a long drive.

 

MPG has more to do with your right foot then anything else. Unless your doing major HP mods

Mine does it occasionally, my guess is the drive by wire throttle body.

Thanks! Interesting guess on the throttle body. I nearly rocketed into a mini who was slow off a stop light last night well after I'd taken my foot off the gas. Definitely something fishy.

 

MC, did your Cobb simultaneously increase HP and gas mileage? As I understand, you have to choose one or the other. Is that correct?

not necessarily. with a good tune your MPG shouldn't really change. there's a chance it can go up, and go down. it really all depends on how hard you are on the gas pedal, and being harder on the gas usually comes with power mods...so you can feel all that well spent money.

 

the AccessPort has an "economy" map but I've heard mixed reviews. it just limits boost, I think. if I'm ONLY doing highway driving I can average in the mid to high 20's MPG using cruise control, but my daily commute ranges from 20-40mph so i get knocked down to around 22-23mpg for average.

 

every now and then I'll pay attention to the MPG and try to drive for maximum MPG (mainly on my work commute) but then I realize it's meaningless and just wait until the tank empties and fill it up again. trying to maximize MPG takes all the fun out of driving.

 

I've had my "A" Trip meter running since I bought the car (16k miles and 10 months ago) and I think my complete average is around 21-22mpg. though I dont know if that resets when the ODO rolls over from 9999 to 0

The surge after letting go of the gas isn't uncommon. You get used to it after a while and you learn to hit the clutch when you need to when it happens. It's just the drive-by-wire system in the LGT.

 

every now and then I'll pay attention to the MPG and try to drive for maximum MPG (mainly on my work commute) but then I realize it's meaningless and just wait until the tank empties and fill it up again. trying to maximize MPG takes all the fun out of driving.

 

 

Nice to know I'm not the only one that's tried that and give up.

OP: mine has never done that in my 44K miles of driving, must be a weird sensation. Maybe something in your throttle by wire mechanism needs to be checked out, sounds like something maybe getting stuck briefly so your engine still thinks its supposed to open up after you take your foot off the gas.

MC, did your Cobb simultaneously increase HP and gas mileage? As I understand, you have to choose one or the other. Is that correct?

 

I haven't noticed any decrease in mpg. That's the beauty of a turbo. Keep your foot out of it and you can get good mpg. The power is ready whenever you want it.

 

When we drove our Honda Civic with a 1.6L single cam and a GT35R on the street it would get 32mpg. As long as you kept your foot out of it. BTW it would also spin the tires in a 3rd gear roll on when the boost hit.

Thanks to everyone for your replies.

 

I know it's best to keep off the accelerator for best MPG, but that is too hard. I compromise by I hitting it hard up to the speed limit, but I'd like to see a little bit of a gain in mpg once I'm going the speed limit on the highway.

 

P.S. That is awesome about the GT35R!

Yeah, it's the electric throttle that does that. Annoying, but you get used to it.

My question is this: has Cobb fixed that mapping issue that was causing Cylinders 2 and 4 to fail?

 

As far as gas MPG, my friend has done mentioned mods mentioned by the OP and he has noticed not only a power increase, but gas MPG as well. He gets more punch and response from pressing the pedal slightly, thus saving gas. He loves it. I love his car and mods myself. His car outperforms my new car, and he has almost 60K miles. He even gets better gas mileage than I do when I use the Intelligent mode! WTF???

yeah Cobb fixed that mapping issue in their latest maps, v1.18

 

edit: that wasn't specifically causing cylinders 2 & 4 to fail, but it probably did not help.