We have owned our truck since 02, the truck was used only for recreation before we got it by a guy with a camper. When we bought it we only used it to tow our trailer, the truck has 60,000 miles on it and until this year had not been driven regularly. Before the truck got good gas mileage it would even get 9mpg towing a 24 ft trailer. Now the truck gets 6.5mpg no matter what. What could it be? Ive put in a k&n drop in air filter, changed the oil, replaced throttle body gasket, ran fuel injector cleaner through the system. There is no check engine light on but when the engine is reved the rpms climb high and drop extremely slow (about 3-4 seconds to go back to idle.) There is also a constant tick from the motor that you can hear inside the cab at about 2000 rpms. The motor runs great otherwise and has alot of power. Please help me. Im 17 and paying for gas is not fun with this truck. Thank you to anyone who helps!

 

Look down inside the intake barrel through the throttle body for oil at the bottom. The slow return to idle and poor gas mileage sounds like a blown plennum gasket. Another way to check is to start the truck and pull the dipstick. Place your finger over the tube and feel for suction. If there's suction, it's blown.

 

either plenum is bad or you need a tune up plugs wires cap and rotor

 

Also check to see if your cat is plugged with junk because that will screw it up too, but you would probably feel a loss in power.

 

Can anyone else verify that pulling the dipstick and checking for vacuum is a decent way to test the plenum?

 

yep,,thats what i was going to suggest as well as an 02 sensor could be bad,,if its time to do a tune up,,before changing the plugs and oil run a can of seafoam through the brake booster,throttlebody,and a little in the crankcase,,and follow the directions in the can,,once done,,change your plugs,if needed the wires,and oil immediately...that helped my gas mileage and was beneficial in the power department lol,,as it truly seemed to run better as well,,as far as the ticking,,it might just be a lifter,,or check your belt,,

 

You have to plug up the PCV valve hose and the nipple where it's connected to the intake manifold, and also remove the breather hose from the air intake and plug it. Then you can check at the dipstick tube. Only do it for like 30 seconds, no more.

 

tested to see if the plenum is good by starting the motor and removing the dipstick and placing my finger over the hole and there was no suction. i think im going to replace my 02 sensors.

 

SORRY! But that's NOT how you check the plenum! You can check it the way I suggested or you can do it this way, http://dodgeram.info/tsb/2000/09-05-00.htm

Or you can do it however you want, good luck.

 

Pull your air intake off and look down the throttle body into the plenum...if there is no oil pooling, you're probably ok.