mine starts fine with one glow cycle down to about 5F. below that i have to let the glowplugs cycle the full 45 seconds and crank while holding throttle to get it to catch. as long as i hold it at 1000 rpm or so for 30 seconds after start it idles fine. if i don't it misses and rattles for a bit and can die. all this though is mostly due to the 8mm M pump making it cranky. it likes to ping and lope a bit at idle when cold and smokes some but that all goes away once its warm. i always keep a bottle of Power Service additive in the trunk and swap between silver bottle and white bottle depending on the season. i have only once had issues with jelling fuel and that was when i was in chicago and it hit -15F for a few days. i ended up using a blowtorch on my steel fuel lines under the car to melt the fuel then started it with a heat gun set on low pointing at the fuel feed line into the lift pump.

__________________
1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P