Bad fuel mileage

[MongoVB]

I get about 10 or 11mpg unless I use some kind of additive. I have been running Diesel Kleen and it brings my mileage up to around 15 or 16 around town which from what I read, is about normal. I have a 4" exhaust, Tymar intake, and I replaced the fuel filter about 3 months ago. I do have a glowplug circuit error code P0380 I believe, but I dont think that would cause drivability issues just starting issues right? I also have a DP tuner chip installed and seem to get better mileage running stock vice the 80 econo tune. Any ideas?

[jamstoyz]

whens the last time you cleaned or changed your air filter? also get a oil change if your due. clogged air filter drops your mpg's

[MongoVB]

Originally Posted by jamstoyz

whens the last time you cleaned or changed your air filter? also get a oil change if your due. clogged air filter drops your mpg's

the air filter is 3 months old. Switched to AMSOIL synthetic at the same time and running AMSOIL dual bypass filter. Tires are also filled to 65psi which is the max rating for the Toyo Open Country AT's.

[dieseldan2005]

You could have a boost leak. Check your CAC tubes. Boost leaks= less mpg. Also do you have any brakes hanging up? I had my rear caliper hang up on me and was costing me mpg's.

[MongoVB]

One thing I forgot to add is I am running a streight pipe exhaust. I have read a couple of posts about loosing mileage while running streight pipe, but I dont think thats it.

[MongoVB]

If my boost tubes were leaking, would I reach almost 30psi at wide open? When I drive aorund town my psi usually only makes about 5 to 7 psi in stop and go traffic with the rpms staying below 2000 rpm's. I just had the boost tubes off along with the x pipe(intake) looking for cracks in all the rubber boots. Everything looked good.

[dieseldan2005]

yeah thats probably not it then, but i figured i would run it by ya.

[MongoVB]

I'm wondering if that glowplug circuit fault could be an issue. The truck starts normal, so I really havent worried about it.

[NCHornet]

NO!!! The GP error code won't affect milage and DieselKleen is good for 1-1.5 mpg not 4-5! If it did it sure doesn't for me. Miage is affected by many variables, most important is tire pressure, try runn'in near max pressures, clean filters both fuel and air. The other big variable is your right foot, keep engine below 2000 rpm's and boost as low as possible, take off's need to be nice and slow. Getting good milage takes work. 15-16 around town is good milage, depending on rear gearing.

NCH

[MongoVB]

Originally Posted by NCHornet

NO!!! The GP error code won't affect milage and DieselKleen is good for 1-1.5 mpg not 4-5! If it did it sure doesn't for me. Miage is affected by many variables, most important is tire pressure, try runn'in near max pressures, clean filters both fuel and air. The other big variable is your right foot, keep engine below 2000 rpm's and boost as low as possible, take off's need to be nice and slow. Getting good milage takes work. 15-16 around town is good milage, depending on rear gearing.

NCH

Well my right foot is under control. I noticed that driving the truck like an old lady, resulted with less mileage. I do drive slower than most and always try to keep it under 2000. The filter is only about 3 months old and does not appear to be clogged. The fuel filter was changed about the same time. Tire preasure really didnt matter. When I first got my new tires, the goodyear shop only put about 42 pounds in them and I drove it for about a month like that with no real change. Since then I have been running at the max preasure of 65psi. No real change, at least nothing I noticed. I usually hand calculate my mileage but I don't fill up everytime. I love driving my truck and if I fill it all the way up, I will drive my truck everywhere and go through 100 bucks a week in gas. I really do notice a noticeable drop in mileage though when I don't use diesel kleen. Could the pump be an issue? I guess I need to check the preasure.