ok here is the problem and i am stumped as to y:

88 honda civic (automatic+all stock): at idle, the car about every 5-7 seconds will rev itself up to about 1600-1800 rpms and go back down. the problem is that no one is hitting the gas lol! umm i was thinking something along the line of a throttle position sensor or something like that but i dont no. my buddies 88 teg rs had the same problem but before we figured out what it was it went away by itself. the civic does not seem to be so good to us lol its been doin it for about 2 weeks aprox. i really have to hold down the brake hard when i stop so it dont jump. also does it when tryin to park lol not kool im gona hit something when it jumps any one ever have this problem or know what it is, any info would help.

thank you

 

Possible vacuum leak. Mine does the same thing. It comes and goes. Check all your vacuum hoses on the intake manifold.

 

EACV

 

what does that stand for

 

idle air control valve

 

ok now is that a definate thing or is it also possible that it could be a vacuum leak? and where is the idle air valve located? would that be in the intake mani?

 

Same problem here occasionally.

 

When the ecu sees the idle speed go higher then spec with no throttle change it shuts the injectors off. Thats why it goes up then down. Something is causing the idle speed to go too high, could be vacuum leak, idle motor etc.

 

it is definetely a vaccum leak not iacv, had the same problem on my 00 si with the cruise control vaccum line. check all vaccum lines to the engine, and intake manifold( even check on the back cuz thats where my problem was and didnt look back there).

 

thanks everyone for all the help. im gona give it a try tomorow and check all of my vacuum lines and stuff. let you's know how it works out

shane

 

i would replace all of your vacum lines and check your tb and intake gaskets, you check gaskets with a little propane tank turn it on (dont light it just let the propane leak out) and go fully around both gaskets when if you have a leak your engine will start revving when propane gets on it.

 

ok found the problem it was a vacuum hose leak i had a small crack in one of my hoses and it was dry rotted so i replaced it and now i am fine. car runs like its supposed to. thanks every one for the help it is apreciated