Car wont sart cold. It can only be started cold with a puff od sarting fluid. When it starts it runs a little rough getting smoother as it warms up. Engine sarts normal once warmed up. There are No check engine light on & no codes stored. I Have changed the spark plugs doing acmpression test at the same time all cylinders 155-165psi. Checked all ignition wires for proper resistance good. Noid light on injector plug shows injectors getting pulses. Cleaned MAF still no cold start. Unpluged MAF still no cold start. Checked for vacum leaks using propa ne with engine running. No sign of leaks. What could be causing it not to start cold?