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49
votes
9answers
13k views

What are the benefits of premium (high octane) petrol?

Here in the UK it's common for petrol (gas) stations to offer both regular and "premium" unleaded petrol. The premium stuff is (naturally) more expensive, and I've often wondered what the actual ...
44
votes
9answers
11k views

Does the amount of fuel in the tank matter?

As long as there is some fuel in the tank, does the fuel level matter? In other words, is it advisable to make sure the tank is mostly full most of the time, or is this just silly? In other words, are ...
33
votes
5answers
45k views

How long does it take for gas to go bad?

Approximately how long does it take for unleaded gasoline in the tank and fuel lines to become unusable in a car that is not being used? What causes this, and what can be done to prevent or remedy ...
20
votes
8answers
35k views

Will higher octane fuel improve gas mileage?

I've heard from some people that high octane fuel will increase gas mileage. Around here, we have the basic unleaded(87), mid-grade(89), and premium(93 or 91). I've been using the basic 87 unleaded ...
10
votes
9answers
9k views

Diesel vs Petrol motorcars. Pro's and cons?

I realize this may be a silly question to those of you on here who are proper petrol-heads and this may even be a repeat question, but I could not find anything on it on here, so here goes: What are ...
10
votes
6answers
10k views

How to properly dispose of old fuel?

I have some old 2 stroke mixed gas I need to get rid of. This could also apply to old fuel removed from a sitting car or any vehicle for that matter. What is the proper way to dispose of this? Are ...
10
votes
1answer
3k views

how to optimize fuel consumption by changing the rear differential ratio?

Is it possible to improve the fuel consumption (decrease it) in my van by changing the rear differential ratio? I would like to optimize it for low-speed driving about 40 km/h (25 mph). Is it true ...
9
votes
5answers
6k views

How to improve fuel economy in high-mileage car?

I'm driving an 2003 Acura TL 3.2 with 177K miles on it. I bought the car with 110K miles on it. It seems to me that the car is not getting the same fuel economy that it did when I acquired it. I ...
9
votes
3answers
9k views

How do I safely siphon gas from a tank?

Our 2003 Windstar was recently totaled in an accident (everybody's ok). This happened the day after we filled the tank. Before we hand over the car to the insurance, we'd like to get the fuel out of ...
8
votes
4answers
17k views

Why should the fuel petcock valve be turned to “Off” position when not using the vehicle?

It’s mentioned in the user manual of my motorbike, that when not using the vehicle, I should turn the petrol tap (the one that has three positions “On”, “Off” and “Reserve”) to “Off” position. I don’t ...
7
votes
3answers
2k views

Cleaning fuel injectors?

I took my car (2006 Honda Civic) to firestone to get an oil change and they told me I should get the fuel injectors cleaned. I was in an Advanced Discount Auto Parts store the other day and I noticed ...
7
votes
3answers
2k views

Difference between high octane and low octane?

What is the difference between high octane and low octane fuel? I'm not asking if one is better than the other for my vehicle, specifically, but rather what occurs differently both scientifically and ...
7
votes
1answer
600 views

how can I measure the amount of fuel injected into a diesel engine in real time in a purely mechanic pre-OBD vehicle?

This is a Mercedes-Benz 308D van, year 1992, model 602.316. Pre-OBD, no electronics of any sort, everything is purely mechanical. I would like to retrofit a system which would measure the precise ...
6
votes
4answers
1k views

Subsitute for Leaded Gas

I have an old '73 240-Z that I am fixing up in class. Once I get it running, will I need to add something to the gas? I know that old cars ran on leaded fuel, the lead lubricating the parts as it ...
6
votes
3answers
4k views

Is high octane fuel a requirement for high-compression engines?

I own and use a 2005 Chrysler Crossfire SRT-6 as my daily commuter vehicle. I'm not interested in trying to eek out a few extra miles on a tank, I want to keep the vehicle and its engine running as ...
6
votes
3answers
20k views

Are fuel system cleaners (like Gumout) worth using regularly?

Are fuel system cleaners (like Gumout) worth using regularly?
6
votes
2answers
4k views

Test Gasoline for Water Content

I live in a small town, and the Gas station there has a bad reputation for gas quality. With rumors like peoples gas tanks freezing solid and such. Is there a quick, safe, cheap way to test for ...
6
votes
5answers
7k views

Doing my own fuel induction service - how to, and how difficult?

Was recommended to get a fuel induction service for a 2002 V4 Camry, and am considering doing it MYSELF. The reasons for considering this are: My car idles a bit rough, especially when the AC is on. ...
6
votes
2answers
2k views

Power loss in truck - triage options?

I've asked at least one question about my specific situation earlier, but at this point, I'm looking for information on how to operate in triage mode, my primary goal is to get my truck working well ...
5
votes
4answers
1k views

Does the tachometer provide any indication of fuel usage?

So, I'm driving along on the highway with the A/C blasting when I notice the price of gas. It makes me think, "what can I do to increase my fuel efficiency?" Some of the tips I've heard have included ...
5
votes
2answers
1k views

How to know how much fuel is left when the light turns on

In general, where can one find information about the quantity of fuel that is left in the vehicle's tank when the warning light turns on? More specifically, in a Suzuki Swift GLX (auto) 2010 model?
5
votes
4answers
825 views

How to tune the ECU / fuel trim in a custom-built engine

I have a Gen VI 454 in my Suburban that needs some work. I'm thinking about turning it into a 496 stroker. Once I find a list of mechanical components (crank, cam, pistons, heads... everything) that ...
5
votes
5answers
21k views

Racing Fuel (100 Octane Rating) - Better than Premium?

Earlier today while driving out East on Long Island I stopped to fill my tank with gas, and at the station, all the pumps had the usual Regular, Mid, Premium on one pump, but on the 2nd pump which ...
5
votes
4answers
237 views

Is it even possible to buy gasoline anymore that does not contain ethanol in the US?

I can't remember the last time I went to a gas station and it didn't have a notice that the gas contained some quantity of ethanol. As I understand it, ethanol is harder on my engine than regular ...
5
votes
3answers
145 views

I'm looking to buy a new car and I'm wondering what does more damage on a car: time or miles?

So the title is pretty self explanatory. I'm looking at getting a minivan, and there is a 2011 model with 50k miles, and a 2008 model with like 30k miles. What's better? Is it better to have ...
5
votes
2answers
10k views

What happens if you put the wrong kind of gas in your car?

I (like most people) just use regular unleaded gas in my car and always have. But once I accidentally put in the premium kind, mixing it with the unleaded that was already there, and I thought for ...
5
votes
2answers
381 views

Is it okay to run aviation fuel (100 low-lead) in a dirt bike?

I'm wondering if it will be okay to run 100 octane low-lead aviation fuel in my 2007 RM250 motocross bike (two-stroke). Half of the people I've asked say yes, while the other half say no. Will it be ...
5
votes
2answers
481 views

What are the causes of fluctuating intake manifold vacuum

I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. I also get occasional fault codes from the ECU indicating a vacuum leak. Today I connected a ...
5
votes
2answers
1k views

Car is sluggish, jerking and idles rough.

I have a VW Polo Classic, 1.6L. Just recently it started to be slightly jerky when in idle and whilst driving. There is also a loss of power, a strong fuel smell, and sounding slightly like a VW ...
5
votes
3answers
727 views

Car stalls when braking (VW Mk1 Golf)

I have bought a Mk1 Cabriolet that has been sitting for over a year. I am trying to get it road worthy. So far so good, but I am having an issue with the engine and braking: The engine stalls when I ...
5
votes
2answers
512 views

1993 Jeep stalls on acceleration, floods, hard to start

My 1993 Jeep Wrangler has about 200,000 miles, in good shape. It usually starts right up, but it's started intermittently flooding, so that I have to crank and crank with the accelerator all the way ...
5
votes
4answers
492 views

Engine repeatedly dies at shorter and shorter intervals this cold morning, finally won't start

I have Pontiac Grand Am 2004. It's been needing some regular maintenance, but other than that runs mostly fine. When I went out to start it this morning, it started fine. I went to start brushing snow ...
5
votes
3answers
139 views

Is the fuel in my engine under pressure?

I have a 2008 Seat Leon FR TDi and need to change one of the fuel pipe (which has become torn slightly). The hose is ~ £50 + VAT so I am keen to do it correctly. Can anyone advise if the fuel in my ...
5
votes
2answers
406 views

BMW 530xd E60 2008 diesel possibly fuel pump problem

Car details: BMW 530xd E60 2008-05 Diesel 170kw. The pump is working as it should be, it has been tested in BMW center. Problem is, when I turn the ignition on, the check engine light doesn't come ...
5
votes
2answers
6k views

Can I use lower octane fuel at high elevation?

Here in Colorado, gas stations sell "regular" gasoline which is rated at 85 octane ((M+R)/2). In most of the rest of the US, 87 octane is the lowest grade available. (As noted previously, higher ...
4
votes
8answers
8k views

When given a choice between octane 89 and 93, which should I choose?

I just recently got a 2005 Volvo S40 with a turbo engine; I want to take good care of it, so naturally, when the instruction manual recommends 91 octane fuel but says it takes a minimum of 87, I have ...
4
votes
1answer
98 views

Why are V engines less smooth?

I'm learning how to ride a motorcycle on a Suzuki Gladius SFV650, with a V-twin engine. But I also had the chance to ride a Kawasaki ER-5, which has a parallel twin engine (550cc). I've noticed that ...
4
votes
2answers
168 views

Proper fuel for motorcycles?

I've heard that regular petrol (92 octane ULP) from some fuel companies is not good for motorbikes as it is intended for cars only. Is this just an old wives tale?
4
votes
2answers
353 views

Switching to a higher octane

This may be a very noob question to ask. But I recently got this car and was used with 92 octane petrol. However, to my negligence I overlooked the user manual which states to include 95 octane ...
4
votes
1answer
1k views

Is there a standard for how much fuel is left in the tank when the meter reads empty?

I know this question is very similar, but I am specifically talking about the fuel gauge and not an indicator light. Almost every car I've owned could run for quite a while with the fuel gauge reading ...
4
votes
3answers
8k views

Diesel Engine difficult to start

I have a diesel powered Audi A4 B7 (2006) 2.0TDi (the 170BHP variety) with a manual gearbox, which I've owned for around 18 months. The car has just short of 100k miles and has a full dealer service ...
4
votes
2answers
819 views

Add 2 stroke oil to a 4 stroke petrol engine during burn-in period

I'm planning to get a new petrol (gasoline) car soon. A friend of mine, who worked as a motorbike mechanic when he was young, told me he puts a small quantity (125 ml / 4 oz) of 2 stroke oil in the ...
4
votes
2answers
5k views

Why does my engine perform poorly and get bad gas mileage after using fuel injector cleaner?

At the advice of someone at a local auto parts shop, I poured a bottle of fuel injector cleaner into my gas tank. This happened around the same time that I had a brake job done and rotated my tires. ...
4
votes
2answers
125 views

Is the ECON button just a placebo?

I recently bought a Honda Civic that had this in the car: I have no idea what it does, and how it's supposed to help. Even Honda's website is ambiguous, just using a lot of fuzzy words to describe ...
4
votes
3answers
1k views

Why can't I fill my gas tank in one go?

For the past couple of months, I've been having trouble filling my gas tank. I have a 2003 Hyundai Elantra, which has a 55-liter tank (approximately 14.5 US gallons). When I buy gas, the pump clicks ...
4
votes
2answers
138 views

Intermittent stall at idle

I have a 98 Saturn sw2 with a recent problem. Two times now it has stalled while idling and when it doesn't stall it floats near 500 rpms (Usually 750 - 950). The first time, it would start and just ...
4
votes
1answer
2k views

2008 Ford Mondeo 2.0 TDCI cranks but won´t start

Ok, so I´m having this problem with a 2008 Ford Mondeo mk4 with a 2.0 TDci engine code AZBA, same one Peugeot uses in other cars such as the 407. Car was having trouble a few days back to start ...
4
votes
2answers
976 views

2010 Toyota Corolla - pumping gas - the gas pump kicks off constantally

In another forum someone said "Screen down the fillneck may be partialy plugged up with matter." Is this something a neophyte can change or fix himself, or should I take it to an auto shop? How can I ...
4
votes
3answers
13k views

What would cause a car to lose power a few seconds after starting, then run normally?

I start my 2003 Honda Civic each morning and drive to work. A few hundred feet down the road, the engine will sometimes behave as though it is running out of gas and lose power momentarily. It ...
4
votes
3answers
2k views

Could a faulty fuel level sensor cause a vehicle to stall?

I have a 2007 Hyundai Santa Fe with just over 90,000 KMs and recently the fuel gauge started to fluctuate wildly. I had the sensor's replaced and filled the tank and it only showed half full. So one ...