OK, new to the forum hope some of you tech heads can point me in the right direction.

To Start, i have aftermarket headers that came with the dodge when i bought it, after driving it a few months i could hear a ping from the drivers side header. I took it off to find tons of cracks in the welds. Got that fixed.

Before all that i noticed i was slowly loosing power and MPG was down, but not to much 10.5 city driving. But after fixing the header i really didnt notice much of any gains other than it being quieter. So i reads some forums and look into plenium issues, took of the air filter and looked down inside and could see fresh clean oil at the bottom, so looks like that gasket could be leaking unless something else would cause oil to get in there. After that i looked at the plugs, they were toast, 1 of them was all the way burnt off. Replaced those and i did noticed a difference in power but still seemed slugish, and by slugish i mean off the start not much power and when driving down the freeway ive got to floor it to get above 45 for it to take off. I had a code p0138 so i took off the o2 post cat, and it was white and chared, and pre cat o2 looked the same. I took out pre cat 02 and fired it up and it seemed like it grew some ***** again, much more pep and throttle resposive. Im guessing maybe my cat it shot, and plenum as well. I can wack my cat and here slight rattle, but im leed to belive, cats plugged since i get more power when i remove the 02 before the cat, and exhaust fumes can escape?

Along with that i hear some clatter under load once warmed up and driving up hill under load. seems to be just before it shifts down a gear?

Any help would be great. I just dont want to start throwing parts at this and would like some good information with what ive said.

Thanks so much.

 

Fix plenum, change cap and rotor, replace cat and ypipe and 02 sensors. And clean the throttle body and iac while your doing the plenum. Simple as that.

 

Yeah, what that Matt guy said. The cat is plugged, and if it's not already happened, you're racing up toward a cracked head. I wouldn't even start the thing again until the work is done.

 

ditto

 

Thanks guys.

 

After you fix the plenum, and before changing plugs, get a can of sea foam from advance auto. Suck up half the can through the brake booster vac line til the engine cuts off. Let it soak an hour and crank it up. After the smoke clears and it's out of the system, change the plugs. That will clean all the carbon off the piston tops from the plenum leak

Then you can also get an SCT tuner