Hey guys i have a 99 ford ranger witha 2.5L and latley the gas milage ihas been getting worse. It idles rought and is weak going up some hills. i have replaced all the plugs and wires a couple months ago along with a new fuel filter. Any ideas as to whats wrong with it?
You might wanna go to "muffler masters" or a place like that and get the catalytic converter checked. Usually they'll check it for free. I have an 88 ranger that was loosing power and gas mileage big time and it turned out to be the catalytic converter was in really bad shape.
As far as cleaning up your fuel and combustion systems - there is a thread in the Ranger forum which details how to "decarbonize" your engine. I personally have had excellent luck for years with a product called "Seafoam Deep Creep". It comes in both liquid and aerosol cans. I use the power brake line to introduce the product to the engine and intake. After the "soak" it will smoke like a chimney for a while and then stop. This tends to clear up a lot of ills. The aerosol is also excellent for cleaning up your throttle body - do not use carburetor cleaner as it has an adverse effect on the coating inside the body.
Give it a go and keep us informed. Were here to help.