This is in a manufactured home that was put up in the end of 2008 so the toilet it relatively new.

When I flush the toilet it goes down slowly. Water tank fills up ~1/2" from the top of the overflow pipe. None of the holes around the inside of the toilet are clogged. I can't find any clog/blockage in the jet hole. Can't find anything in the drain pipe or the air pip on top of the house. Both the sink and bathtub in the same room drain fine and the toilet, tub and sink in the other bathroom drain fine.

I checked the pressure with my hand of the water coming out of the jet hole. It stops a few seconds after the flapper closes. By that time the toilet is still swirling but it's not going down. I checked the jet hole pressure in the working toilet and it had pressure until the water was gone from the bowl.

So I've got to figure out why the jet hole is losing pressure and need to get it back up. Any ideas?

There is some kind of clog further down the line. MH homes are just the same as stick built homes when it comes to having clogs in the line. Sometimes my toilet at the other end of the house clogs up and my other toilet at the other end of the house runs fine. I live in a 2002 MH and the one toilet gets easily clogged. I find a good plunger works wonders in the slow toilet.

Take off the top and flush the toilet. Watch the flapper. Does it open all the way and allow all or most of the water out before it closes? Look in the flapper hole. I just took a bleach tab out of a new toilet I put in 3 months ago. Lady told me it "wasn't flushing right". Some flappers get distorted and a new one is <$5. Make sure the chain is almost tight to the flapper.

I'm think a bit like ma on this. What happens if you flush and hold down the flush handle for a minute. Does it flush, if so try a new flapper. If it doesn't flush two things come to mind. You say jet holes which makes me think you are referring to the small holes under the rim. There is a larger single hole down in the sump area that starts the siphon action, stick you finger in there (yuk) and make sure its clear. When you flush there should be a strong flow coming out of the hole. Second thing would be to try plunging and/or a toilet auger. Cobra 40030 Toilet Auger 3/8" x 3' (http://www.google.com/products/catalog?hl=en&cp=8&gs_id=u&xhr=t&q=toilet+auger&gs_upl=&bav=on.2,or.r_gc.r_pw.&biw=1675&bih=824&wrapid=tljp1315275937402014&um=1&ie=UTF-8&tbm=shop&cid=11507406811445901386&sa=X&ei=t4RlTpqbOrKMsAKZ59XCAQ&sqi=2&ved=0CDwQ8gIwAA#) If you never used a toilet auger watch this http://www.google.com/products/catalog?hl=en&cp=8&gs_id=u&xhr=t&q=toilet+auger&gs_upl=&bav=on.2,or.r_gc.r_pw.&biw=1675&bih=824&wrapid=tljp1315275937402014&um=1&ie=UTF-8&tbm=shop&cid=11507406811445901386&sa=X&ei=t4RlTpqbOrKMsAKZ59XCAQ&sqi=2&ved=0CDwQ8gIwAA#