1999 Chevy Blazer starting and RPM problem

Would these things also cause the longer starting. The blazer used to start right away but now it takes a few seconds to start up. The strange part is that sometimes it will start right up. But 80% of the time it takes a few seconds to start. This also started to happen around the same time the idleing problem started. Or would a longer starting time be caused by something else. Thanks for your help. I will start checking the things you said to check.

The longer starting problem usually happens when I first start it up or after I let it sit for a while and the engine is cold when I start it. When the engine is hot it pretty much will start right up everytime. But I have gone out a couple mornings or when the engine is cold and it has started right up with no problem. That's the part I don't understand.

I got a fuel pressure tester and a vacuum pressure gauge and hand pump so I could pressurize the system and a Haynes book to see what the fuel pressures should be and how to test the vacuum and the fuel pressures were all perfect and the vacuum test was also good. I replaced the fuel pump 5 months ago. I also took apart the IAC and cleaned it all out with carb cleaner. The IAC was pretty clean when I took it out. The Haynes book also said to check ohm's On the IAC and It showed what terminals to check and it gave a range of what the ohm reading should be in between and the reading I got were good. Anew PCV valve was cheap so I got a new one. I also cleaned the throttle plates. After doing all that I started the blazer up and the idle problem is still there and it still takes a few seconds to start up. After all I did I would have thought it would have cured at least one of the problems but it didn't. Also one other thing that I forgot to mention is that my wife told me that she has been putting more gas in than blazer than normal. Normaly it will get around 20 to 21 mpg and my wife does mostly highway driving with it so on sunday we went for a trip to the coast and after I we got home I filled it up and did the math and we are now getting 11 mpg. After she went to work on mon and tues and some local driving she did 123 miles with the blazer and I went and filled it up and it took 10.7 gallons of gas. I have never seen it use that much gas and we purchased the blazer new in 99. That came out to roughly 11.5 mpg. Something is definetly wrong. The engine has 81,472 miles on it and most of that has been highway miles and it runs great. Do you have any other ideas as to what I could be causing these problems. You would think the check engine light would come on and give a code but I keep scanning the computer and It has no fault codes at all.