Re: what cause the tach jumps back and forth + no upshifting on WOT
 

nar it`s an LX and it has a stock tach.

FYI problem is sloved, the tranny works fine, but the tach itself is not, lol it the needle went crazy whenever i went pass 4K even if i rev it in neutral.
as of the not-up-shifting problem, it`s actually shifting fine but it takes f-o-r-e-v-e-r to hit redline (compare to a d16z auto) i and throught it is not shifting LOL

Re: what cause the tach jumps back and forth + no upshifting on WOT
 

Tach signal is synthesized output from ignitor in distributor. AT shift pays attention to rpm feed IIRC whereas the engine deduces rpm based on CYP/CKP/TDC and so engine revlimit is not fiddled. Not entirely certain of the Civic stuff, but the Accord AT control units I was remanning for a while sure did.

Either your ignitor is bad, or G101/G151 aka thermostat housing ground sucks donkey balls. Smoke it over, see if it doesn't fix the problem.