Well, since I've bought my car it has always idled like crap and acted like it had a slight misfire (I said acted, it could be numerous things, I don't want to debate what it was or could of been). I've always used 87 regular fuel. Well recently the car has been idling really wicked and would stall occasionally at red lights trying to go again. The tank was empty and since 93 was $2.50 a gallon, I filled it up with it. After 30 or so miles I notice that the engine idles much smoother and doesn't seem to have the "misfire effect" it did. I do know there is always the “placebo” effect when going to 93 and stuff, but my mom had to drive the car for a day to work and even she noticed the car was running better.

So, question is, is it just a coincidence, or does it just finicky and will only run right on 93 like some cars only like certain gas stations? There has been nothing to the car that’s changed (besides an oil change) or adjusted, just driven daily to school and back.

Explain the cure, with no reference to the problem? I'll pass on this one.

It's not a placebo effect because you knowingly put 93 in the tank.

Anyways, since you don't want to debate what it was or could have been...but it seems like you're asking exactly that, I'll take a stab at it and give you this link:


An even more specific quote:



TOC Admin
Brando

It's an old car, that the problem. They don't run as smoothly as new ones. Last time I checked there was no codes in the ECU and the plugs all looked fine.

I didn't want to debate what is wrong with my engine, fact there is no problem, runs fune. Just seemed to run a little bit better then before.

What can be done about these carbon deposits?

Russ

87delta, my car has also always idled roughly, and I've noticed it reacts quite dramatically to any additives I put in, or expensive gas.

mongolloyd, I beleive you can get a can of "carb-out" from the GM dealer, and you dump it down your throttlebody and let it sit in the cylinders for a few minutes, and it dissolves most of the crap, and burns out over the next few days. Works well, I used it in my cadillac, and made a big difference.

Seafoam works decent as well. Smokes a bit, but ya know that means it's all getting cleaned out (sorta)