I've been using mostly PLA and "PLA+" but recently I tried PETG and was pleasantly surprised to find it worked OK despite my printer not having a heated plate. In contrast, ABS was a complete failure, peeling off the bed like a banana before it really got going.

The main disappointment was a brilliant white PLA+ from eSUN that looked like extruded chalk and didn't self adhere very well. Also seemed more prone to periodic hiccups resulting in imperfections between layers. The more normal black, white and clear PLA+ were fine, so perhaps there was too much white filler in it.

PETG seems to have a good temperature rating (Tg > 100C) and is reasonably fuel resistant. Polycarbonate would perhaps be even better but I don't know how usable it is - has anyone had good experience with it? I'm talking about inlet manifolds here and may end up using one of the online services to print them in PC once I've proven the physical design.