El original

Just before parking my 2003 Vette for the winter mistakenly topped up 1/2 tank with regular fuel. All was fine for the 15 minute drive to storage and with only 600 feet to go I could feel a vibration upon deceleration (low gear) thru the gas pedal and deadfoot. Parked the car and first thing next morning took the car out, all fine when cold but upon warming up experienced same thing. Question to the forum, could this be the result of regular fuel, has anyone else have this issue with regular, any ideas? Would have to happen just before 4 months storage...cant stop thinking about what caused this vibration!?!
Christmas Greetings, Rob

BWF07

Well I have never run regular in mine, but I have read that you can, as the computer will adjust to it and your mileage may be off a little, but what you have I am not sure it is the regular fuel. Are you getting any codes or warning lights?

Mr.Bill

A stock C5 should be able to run reg fuel with no issues at all.

OneBlueC5

Do you have any mods on your car?

jrose7004

Mine will ping a little bit if I run too low of an octane but no mine has never done that!

Vettmann17

I wouldnt worry about it. If it's gonna bother you to store it with the regular in the tank then just drive it till you burn through it and fill it with premium and see if the vibes go away. My bet would be that once the comp adjusts to the different octane it should feel fine. Most likely a non issue. Merry Christmas to you too and a Happy and Healthy New year!

C5Wolfe

I'd say it wasn't the fuel octane but you may have picked up some water in the gas.Put some gas dry in the tank and drive it for a while.

DeeGee

The ignition should be retarded by the knock sensor if you use low octane fuel. Even if the fuel was so bad that the sensor couldn't cope I can't imagine pinging ever being bad enough to be described as vibration.

I'd say you need to be looking somewhere else.

Vetteman Jack

Unless you got a really bad tank of gas (lots of water in it), I'd say you have other problems.

Evil-Twin

All I can say is OH MY.....what a stupid statement...
Sorry Bill, But Ive seen in our test mules # 7 piston blow out using regular gas over time... knock sensors only correct after the initial knock is detected.. running regular is a killer... Now just think about this... Don't you think, If we could have produced a reliable engine that could put out 350 to 430 HP on regular gas.. Don't you think our marketing department would have jumped all over that???? Most people can't detect ping anyway, or know what is going on inside the engine during this condition..Thinking you can run regular gas is such a bad idea... in the summer time, its even worse... Ive seen the testing and done the research...We said you could put regular gas in the car ( " In an emergency" to get you safely to a station that had premium fuel. OK I'm starting to get the idea that there way to many automotive engineers on this forum with high school educations...That my input has become, for the most part, a waste of my time here. Ive tried to help, offer my 45 years of automotive engineering with the last 5 of those devoted to the development of the C5 before retiring, in this forum over the last 11 years.. Ive gone over and over the urban legends, and the myths.. and the BS by shade tree mechanics... I am NOW convinced I am wasting my time in this forum.....

Blitzkrieg

C5Wolfe

I agree, I think your wasting your time here with us ignorant shade tree types! Perhaps you should "move on" as you say. I've ran regular gas in my Corvette on occasion with no problems like mr. Bill says but then again What would I know! I'm probably dumber than Mr. Bill even!

srs244

and the OP says that he only used 1/2 tank of regular which would still give him a greater octane rating than just regular alone. in addition, he hasn't (and isn't) doing it as a regular diet which i would assume over time COULD produce some problems. how very UN EVIL-TWIN of you (very out of character). sorry if you believe you are wasting your time hanging around with a bunch of shade tree types. forgive me if my presence here is below your stature.

c51stvette

perhaps Mr. Evil could clue us in on what type of testing blew those motors with the regular gas. I know you don't have to be on the throttle hard with an engine that is sensitive to pinging. Sometimes a part-throttle up hill run will set an engine off. If I drove my car daily on flat land in cool weather I might be tempted to try some regular to save a few pennies. But I only drive mine in the summer so I go with the premium.

Yello95

I totally disagree with the above statement in red!

Since I bought mine new in April of 2004 I have never run regular...always used premium and have never had any kind of problems as the op has stated...and as most people with common sense would say..."if you disagree with the engineers who are responsible for developing the C5 then YOU need to move on" because YOU are the shade tree wannabe mechanics that are usually full of chitt when it comes to advice about the C5...

killain

Yeah know Bill, Just last week in New Jersey, the state dept. of weights and measures went through 15 independent gas stations testing the gas as it is advertised for octane. Of the 15, 12 were selling regular gas that was posted as Premium 93 octane, In fact some of the regular gas being sold as regular,. . . wasn't even 87 octane. So anyone running their engines on regular are flirting with disaster. Short story which I think you'll appreciate.

Last August1 I bought a 2007 Pontiac Grand Prix with the L32 engine package. 3800 series III V6 with a Eaton M-90 self oiling supercharger. Now this car was a 39 month lease and I bought it once the lease was up. The car ran very well until you were on say RT.95 were it seemed to flutter at any real speeds. I put in a few bottles of Chevron Techtron. But the real problem came on October 1. I went out and the car wouldn't start. No matter what the engine wouldn't start, it seemed like it was trying but couldn't catch. Car was towed to dealership as it was still under GMPP. Car started right away once at the dealership. They went through the engine with a fine tooth comb, but Nothing was a miss. Car came home, one day later, Car no start, towed again, once at the dealership car started fine. I called GM/Pontiac who I have to say were so intense with my problem it really shows that GM is a new Company.

OK, to cut to the chase, here's what the problem was. NO ONE EVER READ THE OWNERS MANUAL. On page 38 it clearly states the car must be run on at least 91 octane, and absolutely no more than 10% ethanol blend. The problem was that when the temperature dropped below 40 degrees the incoming flow of air/fuel mixture, the density of the mixture could not get past the huge amount of carbon/muck deposits on the intake valves before the valves closed for the piston and combustion took place. The dealership did a major Fuel system flush and that took care of 75% of the problem, and I add a bottle of Chevron Tectron with every fill-up of 93 Top tier gasoline from one of the stations listed as a top tier fuel, I use Shell 93 or ExxonMobil 93.

But the real problem was No One ever read the owners manual. and as far as pinging. . . this car has a audio system called a 9 speaker 'Moonson' system. The people who leased the car, They couldn't hear any pinging if it was pounding on the underside of the frigging hood with a mallet, and anyway, it's a lease car so just put the cheapest gas you can find. That was their mindset. But the engine was run on 87 octane for the last four years. I'll have to add a bottle of Tectron for the next year or so. So for anyone out there who are under the assumption that gas is gas, you are SO WRONG ! It's so strange that here on the forum we argue about what motor oil is best and what is the best thing since sliced bread but we never talk about Gasoline. And the quality of Gasoline in our country is getting worse with each year, as long as the oil companies can cut a corner here and there, they'll go for it.

And Gasoline quality has suffered for a longtime. Between the EPA and the free-Market system of gasoline refiners, what they are selling out there is so sad it really shouldn't even be called Gasoline. Gas, 93 octane around here in South-east Pennsylvania is about $385.9 and AAA spokesmen says it'll be closer to $4.50.9 by next spring. A few years ago when fuel prices shot up to $5.00 a gallon, they claimed they didn't have the refining space and no new refinery's had been build in 30 years., Very Odd, because you know where I live we have, or I should say we had 5 refinery's and all but one are closed. Sunoco had two, they are now closed, Velasiro Co. had one, It's been closed for two years now. and Chevron had one and it's also mothballed. Only Amerada Hess refinery is still operating.

So to all of you folks, when the price of gasoline starts to head towards $5 a gallon next summer and the oil companies start to complain about not being able to refine gasoline, Their a bunch of lies, and they know they have you by you know what. Plus the quality of Gasoline we put into our Corvettes is steadily getting poorer and poorer. I've had 5 Corvette and I've never put anything less than 93 octane in any of them. And if you compare the price of filling up your C5 with regular 87 and the cost of filling it with 93 octane you'll find the difference is, at least for me with my 2003 is $0.54 cents. I am never amazed why people buy a Corvette, and treat it like a Cobalt. They'll spend $20,00 cleaner,polish and waxes, but go the cheap route when they pull into the filling station. Crazy, really crazy !

El original

Thanks "KILLIAN", really got this thread hopping...I will phone the previous owner (my b-inlaw) and ask if he had any fuel related experiences. No mods and never any issues with vibrations before so my thought was the fuel. I have had vibration issues in the past with my C3 and it took "2 years to find it", (it finally came off as a water pump failure). So you know why I am stressed. I will put in some octane boost and keep my fingers crossed. Thanks to all. Greetings, Rob

WKMCD

Could be the low octane causing the problem but maybe not. I just wonder what the octane will be when it's taken out of storage.

If the car is modded and been retuned, some quickly "tuners" will not deal with the low octane table since they assume that EVERYONE is going to run 93 or at least 91 if that is all that is available.

It scares me when I travel in the vette to states that only have 91. My car will ping like crazy. That's why I now keep a few cans of real octane booster in the truck when I know I won't be able to get 93.

General rule for a high performance car should be..don't run low octane gas and don't use recycled oil...

And to ET.....not all are deaf.

C5Wolfe

I agree and thank you for understanding what i was trying to say!
If evil twin thinks we are a bunch of people not worthy of his presents then maybe he should just "move on"! I'm sure he knows a lot more about Vettes than I do but he needs to lose the attitude!

Aerovette

B-bye.