is there any way to clear the oil buildup or Gunk? does is also count for the 2.4 liter

Where is it built up at?

If it's inside the engine, you want to remove it a little bit at a time. That way your oil passages don't get clogged up. Perhaps more frequent oil changes with a high detergent oil and a good oil filter.

The Build Up Is Somewhere In The Bottom End Of The Motor Can't Pin Point It And The Car Is Making A Loud Ticking Noise, Not Quite A Knock But Loud Enough To Draw Attention And If Gets Worse When Accelerating.The Car Was Ran With Low Oil For A Short Time. I Just Did An Oil Change And Added Mystery Oil And The Problem Is On Going. IF You Put Your Hand Over The Exhaust There Is Barely Pressure CoMing out.

How dose the oil look after a few hundred miles? Is it showing signs of getting dirty? If so change it every 2000 miles. BTW automatic transmission fluid is high in detergents. I've used it in my diesel engine to keep the injectors clean by adding it to the fuel. You might consider adding a quart just before you change your oil. If you add it Let it the the engine idle for 5 to 10 minutes then drain it all out.

If you have the 2.7, the early 2000's are prone to sludge formation. An engine flush may be indicated. Timely oil changes, and use of synthetic oil is highly recommended. As for the ticking, some valve noise is always present, if more than usual, that is a wear sign, especially if driven under low/ no oil condition. Unsure what you mean regarding low exhaust pressure, if engine runs normally, without check engine light, all systems are running within normal ranges. Catalytic converters can clog under rare circumstances, but engine performance and mileage will be poor, throwing codes and illuminating check engine light. With all these issues, a thorough service check may be the way to go to get to the reasons for these ills, saving you time, $, and inconvenience.