Hi everybodyi am new here, i got my 97 f150 5.4l lariat 7 months ago and i am getting only 10 -11 miles to a gallon doesnt matter if i drive hard or gentle , seems like its pushing hard to go, no body damage or no other problems, i love this truck and i wana keep it, i live in alaska but the 10 miles to a gallon dont seem right, i took it to a mechanic today he said the cats looks like splitting apart, i dont know what he is talking about, help me guys just need some information on how to get good gas mileage and power with speed,thanx.

 

this is my daily drive to work, and i use it for wood once in a while,

 

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Chill bro, you need to give people time to respond, the more trigger happy you are with the enter key, the less inclined people are to help.

First, why would you have a mechanic diagnose the problem first-hand and come to ask us what's wrong? We have no way of knowing without some back-story on the vehicle.

If he's truly a mechanic, and not just someone who plays with cars, do you have any reasons to doubt him? When he says the cat is splitting apart, does he mean that the catalyst honeycomb portion on the inside is starting to break apart, or is the exhaust rusted and breaking off?

What kind of maintenance has been done? Stock tires and gearing? Plugs seem okay? Fuel filter? Air filter? Any codes? What do you mean you have to "pushing hard to go"? What configuration do you have? Does it stumble when you drive? At what speeds? What was your mileage before? Altitude? Fuel grade? Exactly how are you measuring fuel consumption?

There's a lot that contributes to poor gas mileage, maintenance being the key. A tired motor could also be your concern. If a mechanic is saying that one thing is wrong with it, roll with it, and if that doesn't fix the problem attempt the next. Don't let a shade tree mechanic charge you shop prices, if they don't back up their word, and don't pay shop prices if they can't guarantee their work.

 

Mawk's right - what may cause your problems AND ya gotta give us time to respond, dude.

If my mechanic told me my cats were splitting I'd assume that yes, they were splitting open. HOWEVER, many dealers (here in Ontario, CAN., anyway) and most independent garages would show you, because of the repair costs. Crawl under and have a looksee.

Is your 5.4 running alright, aside from the 'sluggishness' and poor mpg? Is it starting ok? Is it idling smoothly? Is it hesitating or stuttering? So many questions...

Although not a mechanic I've been a automotive service advisor, and I know plugged cats can result in your symptoms, whereas the more obvious fixes (fuel filter, clogged fuel lines, fuel pump, etc.) would result in no-starts, stuttering and/or stalling.

As for power/performance/mpg upgrades, I swear by my cold air intake kit and cat-back duals. Probably 1-2 mpg better and a 10-15% increase in power.

Hope this helps.

 

thank you for giving me good advices, im sorry i worked 12 hours today n just came home, i just wanted the truck fixed quickly and took it to the mechanic, he is charging me $800 for both cats as it have dual cats or something like that, besides that my truck has 5.4 motor, starts good, no hesitation, i changed oil , fuel filter and air filter myself like couple months ago, it idles good, there is no codes, i dont know about plugs , and my tires are slight bigger in the first 2 figures but rim size is 16, besides this its all stock, i m sorry i dont know much about these trucks as much as you guys, but you can ask me anything you wana know, thank you again for your replies and btw is $800 reasonable for replacing both the cats and should i ask for the old cats to give me back or no? thank you.( it will be done tomorrow in the morning so should i call him early morning and ask him about the quality of the cats he is putting in and warranty of the cats?)