not using the right gas

[mustangmann9]

my dad got a 98 3000gt (5speed) with 102,000miles, and let my mom drive it and she filled the tank with regular 87octane gas. she didn't know it uses 93octane gas. now the car has a weird low speed low RPM the engine "bucks" and "skips" with semi hard acceleration. my dad tried octane additive but that failed. thanks K.

[xXxRocker5150]

well, even if you have an n/a motor, I dont think the 87 really was what did you in... btw those octane additives don't really work...

either way I'm pretty sure that if you put 87 in it (if you don't do it on a regular basis) that it won't do the car in... maybe there was water in the gas??? that happened with our minivan, and we had to replace the fuel filter... maybe I'm wrong though man, good luck.

[Morphius289]

That sounds exactly like the problem that I'm having. I'm idling really low, and my engine skips. I thought it might be time for an oil change, so I changed the oil, but no luck. If you find out whats wrong, I'd love to hear it.

*edit*
I forgot to add this, but I'm using 93 octane. And one of my friends who is a mechanic rode with me said that it was probably my timing belt.

[Twizted_3KGT]

Using a lower octane than recommended can cause the engine to detonate, which would cause your skipping/bucking under load/acceleration. It can damage your pistons, rods, rod bearings, even throw your timing off and destroy your valves, but only in the worst case. More than likely it won't damage anything and you'll just have reduced power and bucking until you use all the 87 up. That's only IF the fuel octane is your problem. Are you positive it wasn't doing this beforehand?

[AutostradaVR4]

how full is the tank? you can try throwing some racing gas in with the 87, if you have access to it. That may get the oct. level up enough to get rid of your detonation.

I saw on mythbusters that you can use crushed up (powdered) moth balls to increase your octane. I suppose if your desperate you can try it lol. I dont remember exactly what octane they started with, but i do remember that it ended up at like 102 after the moth balls. They were using a chevy 350 and there was no ill effects on the engine.

or you can just syphon out the gas and put premium in

[sLADe781]

This may sound like a dumb question but umm...will it hurt the car at all if all you need is like the regular grade but you put in like premium or whatever? I'm just askin' because if the car was built for a certain type of gas but you change it, what would happen (even if the change was for somethin' better)!?!

[AutostradaVR4]

"In a nutshell, octane is a rating of how much the fuel can be compressed before it spontaneously ignites. Detonation is a result when the air/fuel mixture ignites by compression rather than because of the spark from the spark plug. Higher octane gasoline can be compressed more than a lower octane gasoline before premature ignition. Because of this, higher octane gasoline is said to have a "slower burn". Using too much octane can cause you to lose power though too."

info from daveblack.net

so i would say, unless your car in modded, just run what it calls for. The next step up wont hurt anything, but probably wont help anything either.

[Igovert500]

For the original poster, your dad's car has 10:1 compression, that is high and you need the higher octane to combate knock. The octane boosters claimed they add 10-20 points, but what they don't say is every point = .1 of an octane point. So in reality adding that additive junk MAY have gotten you up to 88octane, but no higher. The best bet would be to syphon out as much as possible, and drive it very carefully, low load, low rpms, etc. If you race it around, or take it to high rpms, you will knock and could do damage.

As far as running better than necessary octane, don't waste your money Slade. On occasion, it will help, for example, I think Young's mom's car had some problems and premium gas cured it. But on a general basis, the higher the octane the harder it is to burn, and so you are actually losing power by running unnecessarily high octane. You should only run what is necessary to retard knock, and no higher. It wont do damage, but it wont be beneficial in most cases.

[Musashi3000GT]

its not the fuel son, I had to roll with 87 oct after hurricane Wilma cause no gas station in south FL had 93. I had it full of 87 for two weeks, granted I kept the revs low...bellow 3000. My engine if fine. I just had the timming belt changed and they checked for compression leaks and all that good stuff. Whatever is wrong with your dads car its not the fuel.

[mustangmann9]

thanks for the help guys. were driving the 3000gt a ton to try and get that gas out. and put some 93 in and see if that works

[mustangmann9]

hey guys, the gas was the problem. we put premium in it yesterday and it runs great. thanks for the help

[xXxRocker5150]

you have one spoiled car ya know that

glad to hear everything's back to normal....