i have a 97cx with a manual y7 motor and a manual y8 intake mani. with the y7 intake it ran fine but after i swapped it the idle surges from 1000-2000rpms. i used the y7 throttle body with the y7 iacv plugged in and just left the y8 iacv on with it not being pluged in(as a block off). thinking that mani wasnt sealing i took it off and replaced the gasket and torqued it all to spec including the tb this time and still same problem. i switched the map and tps it runs funky but when i switch them back the idle goes steady. also when i put my hand over the tb it still runs (like i have a huge vacuum leak). but when i sprayed window deicer all over the mani(to check for leaks) the engine seamed to not be effected by it like there was no leak . i have also taken out my y7 iacv and cleaned it out. any suggestion?

 

make sure the cruise control vacume nipple is plugged its on the right side in the back of the manifold

 

its plugged

 

did you plug the nozzles on the y8 ivac ?

 

reset the ecu,make sure that all plugs are conected, i do the same swap, same problem like u idle like crazy up and down, i set my tb idle and rest the ecu, now is runing good,

disconect the iacv and play with the bolt in the tb,
find the perfect idle for u,
conect again the iacv,
engine its gona rev like crazy again,
turn off the car,
disconect the battery for more than 3 or 5 min,
connect the battery again,
turn on the car
and wait until the ecu read and set the tunnig again

(my bad for my bad typing ) English is not my 1st language!!!, but Honda and mechanic doestn have any language!!!

 

A surge is comon with low anti freeze.

After removing the manifold did you re-up on anti freeze?

 

dude that same stuff happend to me and i just sprayed carb cleaner on it and it worked fine. but that was probably just luck

 

i used a y8 tb gasket instead of a y7(no spot for iacv) my bad thanks for the suggestions