Disco Mike... thanks dood.
Nearly every vehicle I've owned since 1989 (when I bought my first LT1) has had tags stating "Premium Fuel Only". But nearly NONE of them have actually required it. (including but not limited to the current rides: a V8 Benz and a Jag X) This is especially true at this elevation. So teach me: does this one really require premium? Or are you trying to remove variables to help troubleshoot the problems?

Either way, I'm listening. I have very little Rover-Specific experience, so I'm trying to be like a sponge here.

But: I've built and driven and dyno'd and raced waay too many motors in the last 4 decades to think that I should just throw my money at premium because there's a sticker that says so. A fact of combustion is that the lower your octane rating, the more complete your combustion will be in a fixed amount of time (with some variables that can change things, of course). So teach me why You are suggesting premium in this one, 'cuz I'll listen.

And nobody suggested water down the intake. the suggestion was made to remove the 'Y' pipe and run water down the exhaust. But I can see how my use of "throat" threw ya off!

 

One reason for the higher octane has been to prevent or hold to a minimum the build up of carbon and in our heads/valves, it can be a big issue.
The other of course is you will get a little more low end torque and around 1 MPG improvement with 91. I did have an opportunity to run a couple tanks of 93 and boy was that an eye opener, that really woke up my 51 year old Buick engine in my 99 D2.
Might want to look at my major service list posted at the top of this section as a guide to make sure your truck is current, also are you familiar with our front drive shaft issues? When you get a chance crawl under and see if you have 1 grease fitting on each of your 3 front u-joints.

 

allright!
I received my ultragauge in the mail an hour ago. After going through the setup on it, I've got 'er up-n-runnin', and looks like some good info.
So, obviously there's something very different about the O2 readings on L/bank vs R/bank.
Which ones look like they'd be correct? what range should these be in?
And it appears I'm in "Open Loop" mode. IS this BECAUSE of the O2 readings? Or causal somehow?

 

I replaced the 2 front o2 sensors, and it's still popping an 1187. I don;t get that.

anyone? anyone?

grumblegrumblegrumble...