Are these signs of autism in a 3 yr old?

My youngest son just turned 3;learned his ltrs & numbers about a year ago & knows them upside down, backwards, etc...has trouble with colors, tho. Knows many shapes but not as well as letters/numbers.Can say many words- names of animals & various things but can't spontaneously converse with anyone so that we understand him. He has strong inflection, tone & is saying something important- in some other language! He's done that since he was about 15 months. He has good eye contact, will point to things, responds to us calling his name (when he wants to!)& will look where we point him to. His hearing recenlty was checked & is fine, just had 2nd set of tubes in & adenoidectomy. He is recently much, much more short tempered and is VERY clingy to me. I.E...if I don't follow the normal routine for getting an 'ice-pop' from the freezer, he will have a crying fit and refuse to eat it. Same with some other things. He has(since about 10mos) loved taking his hotwheels out of the box and rolling them off the box, one by one, about 50 cars. Then loads them back in the box and does it again. He loves looking thru his books but rarely lets me read one to him. He recently, last month or so, started walking along the kitchen cabinets or walls in various places while staring at the wall/cabinet/etc... back and forth, back and forth. WHen I need to change him, he has a complete meltdown, kicking and yelling, crying and kicking, until I manage to finish, then he's suddenly happy again. Then he says, "no kick me mommy" (I have been saying, "don't kick mommy, don't kick ME, it hurts!" )
We think he has an extremely mild case of trigonocephaly, not noticed except by new pediatrician who reviewed his head circ growth chart because his soft spot just recently closed - around over 2.5 yrs old.  Any scans recommended?  Is this possibly autism of some sort?  THANK YOU!

[Capital H]

I suggest you check this link http://www.nas.org.uk/nas/jsp/polopoly.jsp?d=128&a=2226

which is the diagnostic check for autism in toddlers.

Although this list is specificly designed for 18mths, you could ask yourself how your child would have scored at that age.

Autism is essentially a spectrum disorder which manifests differently in each individual.
The primary symptoms of autism consist of impairments in ability to communicate, to understand social interactions and in social imagination, that is to say understanding social and imaginative play.

A liking for sameness, and distress when routines or environment are changed is one way autism manifests. Unusual language usage another, and often there are sensory hypo or hypersensitivities.

However there are other childhood conditions such as ADHD that need to be considered as well.

[Annie62]

Some of the things your child does is also seen in OCD.  I had OCD as a young child (still do) and had some of the behaviors of your child (including the speaking in another "language.").  When I was four or five I used to speak what sounded like French (of course it wasn't).  I don't know if he has this, but you might want to read on it.  Not sure you will find much info on how OCD manifests in very young children, though, but you could still try.  Of course some of the behavior is also seen in autism as the above poster suggested.  My cousin's son has autism and has/had some of these signs.