First, This isn't your average "Fuel Cap Light" thread so please don't write this off...
Second, I keep good records of my fuel consumption. I do this via ultraguage as well as hand calculations at the pump. I've used the ultraguage for almost 10k miles now.
Third, I believe this anomaly is unrelated to my recent lift because the first 3 tanks of gas after the lift were mid 19mpg to 21mpg. These were a little less than normal for the amount of city/hwy driving per tank, but I assumed lift would decrease mpg.
So I decided to throw a bottle of Gum Out Fuel System cleaner in a tank of gas. I usually try to do this every 3k miles or so and from all that I've read it can't hurt anything. So I had an almost empty tank, put in the Gum Out, and filled up with regular 87 which is what I always use. About 100 miles or so into this tank my Fuel Cap light came on the dash and P0455 on the ultraguage. I sort of wrote it off as I've seen this light before, but more to come on that. Somewhere around there also my ultraguage average dropped from 19.2 to 19.1 (9k miles average) which is odd because this tank was almost entirely highway miles. After 300 miles or so I filled up, and got 18.4 mpg, for a tank of mostly highway miles. This is about 2-3 mpg less than normal for this type of driving. Next tank was ALL highway and I calculated 18.3!
So I've seen this light and code before, once over the summer, and I believe that to be right around the last time I ran injector cleaner. The other time I had this light very frequently was when my cylinder head failed. At that time I was running injector cleaner a lot before I knew it was the head incase it was an injector causing the misfire. Could injector cleaner be the cause of this light/code/leak?
Also, the truck feels very sluggish, and downshifts at even the slightest hwy grades that it doesn't usually leave OD on.
With winter gasoline on the horizon I can't afford to have this type of thing going on. MPG will only get worse with winter gas.
Second, I keep good records of my fuel consumption. I do this via ultraguage as well as hand calculations at the pump. I've used the ultraguage for almost 10k miles now.
Third, I believe this anomaly is unrelated to my recent lift because the first 3 tanks of gas after the lift were mid 19mpg to 21mpg. These were a little less than normal for the amount of city/hwy driving per tank, but I assumed lift would decrease mpg.
So I decided to throw a bottle of Gum Out Fuel System cleaner in a tank of gas. I usually try to do this every 3k miles or so and from all that I've read it can't hurt anything. So I had an almost empty tank, put in the Gum Out, and filled up with regular 87 which is what I always use. About 100 miles or so into this tank my Fuel Cap light came on the dash and P0455 on the ultraguage. I sort of wrote it off as I've seen this light before, but more to come on that. Somewhere around there also my ultraguage average dropped from 19.2 to 19.1 (9k miles average) which is odd because this tank was almost entirely highway miles. After 300 miles or so I filled up, and got 18.4 mpg, for a tank of mostly highway miles. This is about 2-3 mpg less than normal for this type of driving. Next tank was ALL highway and I calculated 18.3!
So I've seen this light and code before, once over the summer, and I believe that to be right around the last time I ran injector cleaner. The other time I had this light very frequently was when my cylinder head failed. At that time I was running injector cleaner a lot before I knew it was the head incase it was an injector causing the misfire. Could injector cleaner be the cause of this light/code/leak?
Also, the truck feels very sluggish, and downshifts at even the slightest hwy grades that it doesn't usually leave OD on.
With winter gasoline on the horizon I can't afford to have this type of thing going on. MPG will only get worse with winter gas.
