My bonneville Sse get poor gas mileage. Ive replace the tires and air filters spark plugs and got a fuel injection system cleaning and new ignition wires.i don't understand why but if the front of my car is sitting up the gauge shows i have more gas and visa versa.I don'tknow if it's the gauge (other ones work fine)or maybe something else.And the gas door has rusted.also when i start my car sometimes it takes a a crank or 2 longer then it jumps. i never drove a new bonnie so i don't know if my acceleration is poor but i think so HElp

I'm not sure if yours is the same as mine, but i'ld suggest every second or third tank of gas get some fuel-ingection cleaner from an auto store like pep-boys or somewhere like that and dump some of that in there. If yours is indeed like mine, after you do that a couple times your gas mileage should improve. Mind you, mine's still pretty bad for my car... only about 16.2 mpg right now, but i still have work to do... and that's a lot better than the 10.5 i got when i bought my car in January:p

If your car is different than mine, sorry, i'm kinda new to cars...

I posted another one of these and i got a response and it said check ur fuel pressure and regulator and fuel pump. I got my fuel injection system cleaned at firestone so i don't think dumping fuel injection cleaner will help. Maybe gass treament but i hear you can onlyy clean ur fuel injectores but so many times before that chemicals eat away at the injector itself. I don't know if that applys to the bottle stuff but just a heads up. And is that mileage u mention on the street. If so bonnies get 19 in a perfect situation so 16 isn't that far off but it sucks.I thinks it's 19 street and 27 highway or 29.

You need to figure out the actual miles per gallon. Fill the tank & reset the trip meter. After you've driven about 100 miles refill the tank & make note of both the miles & number of gallons. Now divide the miles by the gallons & let us know the result.

I'd pull all six plugs & see what they look like. The ceramic insulator should be nearly white on all six. If all six are dark I'd start by changing the O2 sensor. BTW - make sure none of the spark plug wires are touching or close to the O2 sensor. If two plugs are darker than the others you may have a weak ignition coil. Let us know what you find.

I'm not real handy with cars as im only 19 and this is my first car. So have no clue what a ignition coil is but i would like you to explain to me what it is. Since i've bought a car i been learning about it along the way trying to save money. But i got a o2sensor back in october or september, my Cle was on.Also i had to get a new gas pipe and gas cap. The pipe i had wasn't sealing right as they did the smokle test on it(this was fixed at a dealership). The oxygen senser was fixed at good year as i figure it was less important than the fuel line so i saved some money on it. I would of save more money if i knew how to fix it myself since u just have to cut the old one out and put the new one there and conect the wires. But wouldn't the Cle come on if the o2 sensor was out? after i got it fixed it didn't really help like i expected it to(gas comsuption)I live in cleveland so the weather could be 70 today snow tommarow. The suggestions you've mention to me make sence mainly having my fuel pressure checked. Also Driving i usually get to my destination with out the Temp engine gauge reaching the middle. This inculdes a 2 mile street drive w/ one minor hill. next an up hill on ramp and a 6 mile freeway drive to an exit incline ramp. Followed by an 5 mile drive. This drive has little stoping and a combination of 13 miles. Iv'e researched the mileage and 22 is the freeway/street rating. I repeat that same trip home but it's more of a down hill trip. Today i burned a hole block of gas, which i assume is roughly 2 1/2 gallons. So correct me if im wrong but im think im lossing alot of gas!. The guage shows i burn more on the way back then there about 3/4 more:uhoh: .I thought maybe the car thinks it has more gas then it does then as i drive it readjusts. But this is to big of a swing. The information is a typical day of driving.As mention eairler on a full tank i can get about 3 or four days out of 1 block which isn't good. Other than that the car runs great but i think it's just running rich.Or something just isn't working i considered driving on E to see if theres still gas in there and something is making the car get it wrong. The reason why is i was on the freeway and i burned a whole block abd the neddle was under e but it still was driving. it didn't feel like i was out of gas. Thankyou for ur input