My car is getting constantly harder to start after being turned off for a minimun of a 1/2 hour or more. If the car is warm it will usually fire up right away. Anymore than half hour forget it. It takes about good 10 seconds of steady cranking before sputtering to life. It also has a noticeable hesitation when stepping on gas from idle. You step on the gas and it will hesitate once and then kick in and start revving. I've changed fuel filter, air filter, spark plugs (one had quite a bit of oil on it), FPR, MAF, coolant temp. switch, fuel pressure is steady and timing is set at 11*. I noticed on a cold morning when this happens I can see a big cloud of grey, gas smelling smoke come from exhaust pipes. What else can I check? I'm thinking I should get a fuel injector cleaning done. Does that actually work? Should I actually pay to have fuel injectors checked or should I just get em cleaned? Or maybe get spark checked?

 

Set timing at 6* and check for a good spark.