It's very possible... The only problem Gasoline/Petroleum engine face are low Oxygen concentration; hence, low output... I climbed the last climb (Babusir) on my 2005 EXI Civic but mostly in 1st gear and made it without any issue; however when I was leaving Gilgit, I bought myself a tool to open the nuts and bolds of my air cleaner with in case my car never made it to the top. I never opened it though; if any of Your cars face any problem, just remove the air cleaner for some time, that way the airflow will improve. You are not the only one going through this road, dozens of vehicles make it through without any issue. Best of luck...