Walmart carries this stuff... It is made of Impregnated Cloth meant forHigh Temperature and High Electrical Resistance Jobs ...with proper type of "Goo" ...and for not too much money. It's not exactly the "Kosher" GM "Silky Smooth" Fabric Tape... but will be seriously better than the Shiny Black Plastic Typical PVC type tape that simply will not hold up inside of any vehicle insulation application:
I use ul or csa listed tape, but all too often I check a year later and find the tape is falling off the connection. The 3m and walmart options cost a lot more, but if they don't let go then it's something to consider.