The "special thing" is the computer that is programmed for 92 octane premium fuel, when it senses lower grade fuel it retards the timing to adjust to that fuel. You are welcome to drive around retarded all the time but you will get less power and less mpg.

You may not notice the difference in one tank of premium if you have been using regular regularly as the computers adaptive values will take longer than that to re-adapt.

 

I don't see how it is possible for the ecu to detect the fuel grade.
Please explain.

 

Are the D2 O2's and even capable of that?

 

The PO of my D2 said he used 87 in it.
I can have pics of how clean the majority of the inside of the engine was.
I can take pics of the lower intake, intake ports on the head, and backs of the intake valves...they were coated with black gum.

 

I was educated when my mechanic showed me the inside of my engine and told me to stop using cheap gas.

 

"drive around retarded all the time"
lmao!

 

It would be the knock sensors that tell the computer to retard timing to prevent pinging.

 

Ah! ....duh
I knew that, lol
Pinging from detonation, from low octane igniting early under compression, before the plug fires.
I didn't realize they were that sensitive, considering it's a 9 something to 1 compression ratio.
Thanks

 

I run Exxon 93 octane only. I get 12mpg. City and highway, 12 mpg. 250-270 miles per tank. Who cares? These are NOT economy cars.

 

I've run 87 in the 99 D2 since I bought it 2 years ago, I get 14MPG, and it's very peppy on the road for a 4.0L. That D2 didn't cost me hardly anything so I kinda used it to experiment on with the 87 octane. Of coarse I'm not towing anything or driving it like I stole it, but zero issues in 2 years.