My truck boggs down when i'm trying to pass someone on the highway anyone tell me what the problem is? it won't shift down to passing gear if i give it half the throttle it does. any answer?

 

Read sticky about plenum gasket at top of forum to start with. Does it act this way on flat ground with no headwind? If you have it loaded and driving in hilly area may need to drive with od off. And if plenum is blown then 02 sensor and cat will need attention. Can pull front 02 sensor and see if you have more power.

 

i'm not in tow and the bed is empty. when i get on the highway i will floor it to pass a car and it is steady. it does'nt down shift and then take off. i put on one of those after market air cleaner and it did'nt change..

 

guess #1 - could be vacuum leak of a vac line around the engine. symptoms of this are that you hit the gas and it bogs down real bad because the vac drops, then it sort of catches it breath and take off.

guess #2 - throttle position sensor TPS needs replacing. symptoms similar to above.

guess #3 - might be clogged cat, but symptoms of this are inability to rev up over some certain rpm, like 2000 or 3000

 

if i replace the huge muffler. with a free flow muffler do think that would make a differance?

 

no....

 

no.. but a new muffler might make you feel cooler! Check your plenum gasket.. they go bad.

 

i forgot to mention when i took off the old air cleaner i did notice a little black oil on top of the throttle body. could that indicate that the plenum is bad?

 

On top of the TB, or on the inside of the intake?
Read the plenum thread stickied at the top of the 2nd gen forum...
If there's oil on top of the plenum pan UNDER the throttle body, that's indicative of a blown plenum gasket and or PCV valve.

 

lol. if it says Dodge Magnum on the truck, it indicates that the plenum leaks. if yours hasn't been fixed with an aluminum plate, then i'm sure it leaks. that may or not be your actual problem.

i'd replace TPS. $40-50 at any parts store.
and read the plenum thread. you'll need it some day.