I've been getting 15mpg on my 18 mile daily commute trip to work. I've data scanned everything and there are no codes or faulty sensors. The computer has a good grasp as to what the engine is doing and shows all the sensors (including o2's) operating normally.

What gives?

I thought LT1's were supposed to get better than this? I realize I might be a bit of a lead footed driver but I'm mainly highway for all of this and the engine has plenty of time to reach operating temp before I get there. About 7 blocks of city, 7 miles of highway, then 7 blocks of city and I'm at work. Then repeat on the way home. Even on long road trips the best its got is 17mpg.

Its a complete 94 LT1 that I put in an 89 camaro. It has 220k miles on it but runs really strong, no oil or coolant being dripped or burnt anywhere. New opti, decent coil, MSD 8.5mm wires, oldish dual platinum AC-Delco plugs. Everything is stock except for the headers and exhaust.

Can anyone offer some advice?

 

Why not provide access to some of your data logs? Upload them to a file sharing site.

 

Man the interweb is confusing. Hope this works.

haha, I win. Putfile didn't want to make the link work. You can see I was steady up until I stomped on it.

Left BLM is 134, Right is 126

 

My car has been getting horrible mileage for the last couple months, and it has started detonating - I have been using octane boost, and really need to write a winter tune with less timing. The cause is the winter fuel that's out right now - our service department is seeing many cases of this issue too. My mpg dropped 2 full points with no driving habits change.