Just joined Today...MJ Comanche owner
I am the proud owner of a 1989 Jeep Comanche Pioneer 4.0 litre, in-line 6 [Canadian]. Her name is "DWD" [Darkwing Duck]. She is sporting a 'new' reverse-engineered/remanufactured 4.0 L. inline 6 engine with a newly installed Spectre #9945 Cold Air Intake Kit [designed for the Comanche & Cherokee models of those early years with the 4.0 L. IL 6 engines. I also replaced the Fuel Injectors with the newer Bosch 4-spray type III disc type injectors. She has a Bosch Starter and a Bosch Alternator, as well. She is running on Mobil I synthetic oil 5-30 wt [after a 5,000-mile break-in for everything to seat-in]. She idles evenly, after a short warm-up, at just slightly below 500 rpm. Very happy with the performance. Looking forward to sharing info from my experiences, ie: start-up, idle, etc. with my now Fellow MJ Owners on this Site.