Mileage with ported TB
10-25-2006, 08:59 AM
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Mileage with ported TB Ok, last week I put a ported TB on my 98 T/A and it seems like i've lost a considerable amount of mileage, like prolly 2-4 mpg. Is this normal? I'm not sure it's worth losing that much mpg for 5-10hp.
10-25-2006, 09:53 AM
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yea, if anything it would be better. usually when you add new mods, the mileage is worse for the first tank or so. i know mine is because i always wanna see how much faster the car got!
10-25-2006, 12:19 PM
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Hmmmm, Yeah, at first I was all over it. But since then i've been staying out of it. Mileage just seems a bit lower. I'll keep it on and see if anything changes.
10-25-2006, 03:06 PM
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You might want to double check if you plugged your maf and iat sensor back in, and maybe disconnect the battery for 10 mins to reset the ecu.
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10-26-2006, 04:42 AM
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I believe the easy way to reflash your stock pcm is to pull the PCM fuses out of the the fuse box in the engine bay and cycle the the key to the on position without actually starting the car. But i may be wrong it's been awhile since i did anything like that.
10-31-2006, 06:50 PM
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Ok, so now I definately have all the lines connected, no vac leak, and I unplugged the battery for 10 min. as some suggested. Mileage did improve. However, on this last tank I averaged 17.15mpg. That seems low, even for city driving. When I first bought the car the stock tb and the slp MAF were on it and I was getting close to 20mpg. Now I have the ported tb and the stock MAF and i'm getting around 17. My driving habits have not changed. I do get after it every once in a while, but I drive pretty conservatively most of the time. Is it possible that i've screwed something up, or is the new tb to blame?
10-31-2006, 08:05 PM
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I highly doubt the tb would decrease your gas milage. Your o2 sensors might have gone bad, or maybe you need some new spark plugs.
How many miles do you have on your car, and what other mods.
How many miles do you have on your car, and what other mods.
10-31-2006, 08:07 PM
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The car has a little over 48000 miles. The only other mods are SLP lid and flowmaster catback. I have only noticed the decrease in mileage after putting the new tb on, which I understand isn't normal. At first it was real bad because the line that runs into the top was disconnected. I fixed that and it got better, but mileage is still substandard. Is it possible that the pcm just needs time to adjust? If so, how long?
10-31-2006, 08:27 PM
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Yeah, that's true, but I just did the tires. I mean, I honestly thought that 280 miles out of a city tank wouldn't be that hard to get. If the mileage doesn't change after a couple tanks I may go back to the stock tb/slp maf. About how many miles do you get per gallon and out of your entire tank?
10-31-2006, 08:28 PM
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Well its a pretty minor mod, so i wouldnt think the ecu would need time to adjust. Check your tire pressure, if its below 30 your probley gonna want to put some more air in it. I keep 32 in the rear and 35 up front.
If thats not it, just go through a couple gas tanks and record your milage to see if it changes. You could easily loose a few mpg by just driving a few more city miles than usuall, or having lower tire pressure.
If thats not it, just go through a couple gas tanks and record your milage to see if it changes. You could easily loose a few mpg by just driving a few more city miles than usuall, or having lower tire pressure.
10-31-2006, 08:38 PM
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I get around 280 miles until my fuel light comes when i have 13.5 gallons left. But i do about 75% highway driving.
I didnt know you still had your stock tb, I would run 1 tank of gas on your stock tb, and then switch to the ported one for another tank. I really think the decrease in gas milage is from something else, but that should tell us.
yeah i dont know how your post is above mine.
I didnt know you still had your stock tb, I would run 1 tank of gas on your stock tb, and then switch to the ported one for another tank. I really think the decrease in gas milage is from something else, but that should tell us.
yeah i dont know how your post is above mine.