Is there anything amazo can't absorb? like tanks, power suits, etc?

Is there a limit to how much powers he could absorb?

Some versions of Amazo are restricted to only those powers which belong to members of the Justice League.  By disbanding the League temporarily, Superman was once able to shut the android down rather easily. 

That aside, he's even been able to duplicate magical powers.

Mental Instability i think?

Some versions of Amazo also have been known to carry the weaknesses of the JLAers whose powers he has. So for example, he's been shown in many cases to be weak to Kryptonite, fire, etc. because of that factor. Though I imagine Professor Ivo has done some serious improvements each time Amazo has been defeated so he can become more and more of a threat.

Can Amazo copy things like shapeshifting?

@martianmanhunterisbetterthancy: Amazo can copy anything older versions had Martian Manhunter powers,but never demonstrated. He also has the powers of Elongated Man,Ralph isn't on par with MM shapeshifting abilities, but may be considered a shapeshifter.

@matchesmalone21: Well Ralph really isn't a shapeshifter, he has stretchy abilities. Plastic Man is a shapeshifter.

@martianmanhunterisbetterthancy: Actually Ralph is a shapeshifter,though not in the same level than Martian Manhunter and Plastic Man,but he can turn into simple things like balls,balloons...nothing such complex the two above can do

@matchesmalone21: Another thing, can Amazo copy Green Lantern? How does he create constructs?

@martianmanhunterisbetterthancy: Amazo have copied any member and weapons of the Justice League since the Silver Age. He absorbs a portion of the a person then reproduce it over and over,not only that he's also capable to magnify the adcquired powers.

He created rought his artificial intelligence,since he doesn't have emotions...then no willpower.

Could he do something like Copy Spectre ?Or Wonder Womans lasso ?