Check engine light came on for about an hour then went back off..Tried to get it to come back on but couldn't ..Today the car would not start,engine just turned over let it sit for about 10 minutes and it finally started.

The check / service engine light means there is a problem with the performance the engine computer has detected. The flashing light means the problem is serious.
You need to have the engine computer checked for trouble codes to proceed.

Lets start at the beginning.
You say it cranks but will not start, right ?
The warning lights are supposed to come on with the key on and then go off once the engine starts.
If the engine cranks but will not start, someone will need to figure out if it is lacking fuel to the injectors or spark to the plugs, or something else. One way we check it is to look for spark at the plugs, check the fuel pressure, and try starting fluid in the throttle body.

http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f80380329#hd1-1-28 Here is what is listed for problems,couldn't find codePO446,click on link to view.

check for a bad connection like a bad ground at the battery, make sure both terminals are tight at the battery, the starter and the ground at the engine. the shop that installed the EGR should have erased the codes, after 50 to 100 miles you would be able to go through emissions.

check your battery terminal very well and re tight very well

battery is getting low!

fuel pump , security issues, ignition issues

You said you tightened the battery cables, did you check the other end of the negative where it bolts to the engine. When you tightened the cables you also used a battery brush and cleaned the posts and ends?

it sounds like an intake vacuum leak to me. check with propane or acetylene

I'm having same problem on my 2000 model rodeo 4wd 3.2L V6. Other day check engine light came on. I checked engine bay nothing abnormal, or power loss. Next day light was gone. 2 days later driving, a sudden loss of power and light came up. After idling for a couple of minutes, drove off with light still on but all power back. 1 hour later of faultless driving loss of power for a minute or so. Engine temp normal. Had break for 1/2 hour and set off for last hour of journey without fault except check engine light still on. Following dayon startup light went out???
Seeking help from experts.