I keep my cars well maintained, full tune ups all the time. For my Accord 6-6 I only use Shell 93 V-POWER.

So for my 95 Prelude S 5mt I thought it would be nice to enjoy some 87 gas prices over the winter. BP used to be Amoco. (never had issues with Amoco) So I was filling up with 87 BP for a while.

I noticed that my Prelude was only getting around 23-25mpg mixed driving. I figured it was just old (19yrs and 200k) Then I noticed the car was underpowered, and started knocking/pinging.

I checked my timing and all was fine. I thought maybe I got bad gas. I let it run low with careful driving and filled up at a different BP many miles away from home. No difference at all. I let the car run empty again and filled up with Shell 93. As soon as I left the gas station the car was different. Everything was well again. That tank got me 29.1mpg, I filled up again and I'm up to 32mpg.

Is anyone else having problems with BP gas? I'm going to run Shell 87 next tank and see if all is ok. I really don't want to run premium in this car but if the gas mileage is that good, I guess it pays to run it.

 

I use arco all the time which is BP and never had a problem. I never buy into the whole bad gas thing.

 

I don't see how you can judge a difference when going from 87 at one station to 93 at another, much different octane rating, and probably different amounts of ethanol and other additives.

If you want a good comparison, use the same octane from different stations.

Since I don't know fuel in your area, do you have a mid grade i.e. 87, 89, or 91? I know that the Si and vtec models say to use 91+ octane only. Here that is premium, unless I find the rare station with 94 octane, but my car is not tuned for 94, so I don't worry about it.