I have an 89 yj with 4.2l. I use the jeep in Colorado and the carburetor sucks in the mountains. I want fuel injection. Considering the conversion kit..but it's costly to put on a 20 year old engine. Maybe I'm beyer off spending more to get new engine. Can I swap my engine for the 4.0l fuel injected model? Our are there other options I'm not considering?