im pulling out my hair now. my truck is only getting 11 mpg no matter what!!! i was getting 14.5 mpg pritty regularly using the RBP additive, i ran out and my truck droped to 11 mpg, i knew then something was really wrong, i use to get nothing less then 16 mpg. before anyones askes yes this is all hand calced. ok so first thing i did was add the RBP additive back, didnt help, turned my chip down didnt help, last tank i was towing a heavy trailer with horses in it, it sayed at 11 mpg, now this tank i drove about 200 mi on the freeway, guess what..... 11 mpg agen!!!!!! i cant figer this out. im going nuts, no one has any type of ansures everything i check is normal, im getting boost, no smoke. all im getting from shops here is to start changing parts till its fixed starting with the injectors then the VP44, i dont have that kind of money just to buy and check till its fixed, i need an ansure so i can get it fixed and get on my way.

 

I would say VP44

 

Start with the simple stuff first, have you cleaned your MAP and IAT sensors? May not be the problem, but won't cost much and I do know that a faulty sensor will kill your mileage. Good luck.

 

ya i cleaned them, everyone tells me that same thing over and over here, 150k is alot on injectors, they need changed out.

 

Could well be the problem, and it's always a good excuse for an upgrade!!! You might want to have them pop tested to make sure that's your problem though as 150k isn't really all that much for injectors IMO.

 

Is your tire size stock? If it isn't your calculations can be off quite a bit.

 

no there not stock but i have my computer recalibrated for them right after i got them, my milage droped only about .2 mpg average after i got them. all the milage drop happend well after the tires. ya i like that choice cuz i want injectors, but i cant afford to do both.