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Really bad gas mileage!

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Old Nov 18, 2003 | 01:36 PM
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Unhappy Really bad gas mileage!

I'm not a new LS1 enthusiast, but I'm not sure where to post this:

My 01 Z28 has about 40k miles. I used to get pretty good gas mileage.
The last time I drove to Vegas I got about 29. This time I got 23. That's a big difference. Also around town I'm lucky to get 19. I haven't changed my driving style at all. This has been going on for a while now.
One thing it might be, but it just happened is I got a SES code. I pulled the code and it's code #P0357. It has to do with the #7 coil. Also I have never changed the stock plugs. Could this make that big of a difference in mileage?
Thanks for the input.
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Old Nov 18, 2003 | 01:52 PM
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Heck yeah it could. It's prolly the plug, but possibly the coil pack or the wire.
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Old Nov 18, 2003 | 02:48 PM
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you need a tune up homey, same **** happen to me, after new plugs, wires and a fuel pump/filter(one of those) it was back too all good
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Old Nov 18, 2003 | 02:56 PM
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Plug could have folued out. Replace them with NGK-TR55's.
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Old Nov 18, 2003 | 03:34 PM
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I get 19 around town since new. It might be due
to an itch in your right foot....
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Old Nov 18, 2003 | 04:02 PM
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Originally Posted by jimmyblue
I get 19 around town since new. It might be due
to an itch in your right foot....

Ya I get 18-19 most of the time. I think it is due to the same itch.

Adan
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Old Nov 18, 2003 | 05:14 PM
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I definately do have an itch since I installed that pesky Magnaflow cat back but my mileage has been bad since before.

I know alot of people swear by the NGKs but, I have a set of Bosche +4s that I got for free. How good are these. My dad used to use them in his dirt track car when I was a kid. I was thinking of having the dealer change the plugs while I have them check out this SES code/ coil thing. I got a free 100k mile warranty, I might as well use it.
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Old Nov 18, 2003 | 05:28 PM
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19 miles to the gallon..... whats that???? yeah change your plugs and while your in there u might as well change the plug wires too. I dont even get 19 miles to the gallon on the freeway on trips. About 13 in town and 17 on the freeway.
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Old Nov 18, 2003 | 06:49 PM
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Bosch = good in any thing not domestic.
I wouldnt run bosch plugs if they were free, installed for free and I got paid weekly just to keep them in my car.

When I worked at pep boys we had a special on bosch plugs when we stopped carrying every thing else. Probaly 6 out of 10 customers with domestic cars that I installed them in came back. One actually brought back his regal and watched me pull back out all 6 plugs so I could show him they were new, they charged him R+R plug labor a 2nd time

Last edited by ta12sec; Nov 18, 2003 at 06:55 PM.
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Old Nov 18, 2003 | 07:08 PM
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I used to work at Pep Boys. I got the +4s free through a contest. Why don't they work well in domestics. My Dad ran them in his 440 Cuda way back when. How long do the TR55's last? I thought they didn't last very long. Would the dealer carry those. i really don't feel like changing the plugs out right now. i've looked to see how hard they are. It looks like fun.
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Old Nov 19, 2003 | 02:00 PM
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I wish i just had bad plugs. Im only getting 8mpg with no trouble codes. I dont know whats going on. I think i have a major vacuum problem.
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Old Nov 19, 2003 | 02:14 PM
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Originally Posted by sunsetz28
I used to work at Pep Boys. I got the +4s free through a contest. Why don't they work well in domestics. My Dad ran them in his 440 Cuda way back when. How long do the TR55's last? I thought they didn't last very long. Would the dealer carry those. i really don't feel like changing the plugs out right now. i've looked to see how hard they are. It looks like fun.
No kidding... if ya take the coil packs off, it's not near as big a pain..
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Old Nov 19, 2003 | 03:34 PM
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I dropped off the car at the dealer this morning. I have a 100k warranty but I think they're going to charge me for diognostics even though I gave them the code and told them what was wrong. They also will only replace the plugs with Densos. I asked for just an estimate. He also said that the stock plugs were good for 100k miles.
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Old Nov 19, 2003 | 06:10 PM
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OK now I'm pissed!! There's a short in the wireing to the #7 coil from the firewall. You have to take the fuel rail off to get to it. The thing that pisses me off is that my warranty doesn't cover it. If that isn't the biggest crock of ****! $200.00 to fix, no parts just labor and $78 to diagnos. I'll just do it my self thankyou. I'll have my dad help since he's a master tech. What the hell did I get this stupid warranty for! It's useless. I'm thinking of telling them to shove the warranty where it counts and they can replace the #1 piston instead since that's all they said they would do. This f'n sucks!!!!
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Old Nov 19, 2003 | 06:48 PM
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Why doesnt warrenty cover it?
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Old Nov 19, 2003 | 10:07 PM
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Because warrantys are just like car insurance.

They make their money by not paying when at all possible.
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Old Nov 19, 2003 | 10:36 PM
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I realize that but what are their grounds for not covering.
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Old Nov 20, 2003 | 12:03 AM
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Mine can barely get 21 on the freeway in 6th gear cruising at 70! It's always been like this. Just changed the plugs and wires about 2000 miles ago. I can barely get 240 out of a tank. I thought these stories about 25 MPG were myths at first. Maybe I'm just checking it wrong.

Ryan
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Old Nov 20, 2003 | 12:05 AM
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....changed the fuel filter not long ago too.

Ryan
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Old Nov 20, 2003 | 09:18 AM
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Supposedly I have the basic warranty which only covers major parts of the drivetrane (sp?), like internal stuff. So the short in the wiring doesn't count. Also I believe it's state law that if your car is under 50k miles anything that affects emissions is covered underwarranty. The service writer told me it wasn't a component failure it's not covered which is total BS. If I'm getting a miss fire I'm not gonna pass emissions, so it's emissions related. So anyways, I told him I was going to make a call when I was leaving his desk. and when I was getting my car after paying $78 for diagnostics when I already knew what was wrong, he came up and told me he would talk to his service manager. If I had know this was going to be such a big hassel for them I would have fixed it myself and saved myself the $78. Or maybe I should just go trade in on a Cobra or something. GM sucks! I'm going to let them know this too. I used to be a chevy guy. My first car was a Camaro, but I may be going to the dark side. Sorry for the rant.
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