View Full Version : ways to lean out the mixture
10-14-2002, 05:36 PM
My car is getting about 170 miles per tank and it doesn't seem to want to get any better. I thought it was my driving style so I decided to take it kinda easy for awhile with little to no change in MPG. I know it's a V8 but that only adds up to be around 11 Mpg and stock numbers are 17/24.. I don't expect to get that but somewhere near would be nice. I drive all city driving but on the expressway it seems to get about the same.. The vaccum system isn't totally done right when its taken out of a cadillac (no canister) but I am sure I could fit it if needed.
The wiring was just redone, new O2 sensors, Air temp, fuel injectors, FPR.. that seems to be it..
Could it possibly be the MAP sensor reading incorrectly?? The car seems to run just fine but this 170 miles of premium gas per tank is making me look twice at my regal before I leave in the morning..
Any help or ideas would be greatly appreciated..
10-14-2002, 06:17 PM
I have a weird thing too in my 02 Mustang GT, i have a 13 gallon tank and when i put regular in it i can do about 300 miles driving normally and when i drive like a maniac i do about 200 or 190 miles, but weird thing is when i put super gas in it i do about 20-35 miles less on a tank than i do on a regular gas. On my Oldsmobile i do more on super gas then i do on regular. Just my 5 cents.
10-15-2002, 04:13 AM
Well I wish I could try using regular or plus gas but a stock 4.9 caddy motor says that you have to run premium gas and that if I recall right is a 9.5:1 compression ratio and I'm running closer to a 10.5:1 ratio on it now.. I have a Air/fuel gauge I am going to hopefully put in tomorrow to see what the front O2 sensor is telling me..
Anyone thinking it could all be involved in the vaccum system?? I mean there's isn't really any leaks as far as I know I just have the ones that aren't being used that are supposed to go to the purge canister plugged...
Could it have something to do with the EGR maybe?? I disconnected it awhile ago, but even if it was stuck open would it give me bad mileage??
It either needs to lean out or gas needs to become REAL cheap...
it's possible that the higher octane gas is setting off the ping sensor and retarding the timing. Consequently your performance and economy suffer. You should stick to what is reccomended...that might be why the mustang doesn't like it
10-15-2002, 02:54 PM
Well I wish that suggestion helped me out but ther's no knock sensor on my motor so there's no way I even want to attempt lower octane gas... Shit I don't even like using 92 octane instead of 93.. Whatever
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