j/w what cost rpm moving up and down on neutral (5speed). can i get a list of thing

 

vacum leak? check your vacum hoses...maybe you got one thats leakin

 

tps....

 

IACV.

Vacuum leak would be a constant higher idle.

 

^^^ I agree. Especially at start up.

 

When I had my b18c in my coupe, the TPS was bad, but the issue was not a fluctuating idle. The idle would stay high, when in neutral or clutch, until I came to a complete stop then it would return to normal.

I know my issue isn't the only symptom of a bad TPS, but the MOST COMMON reason behind a fluctuating idle is the IACV, or the FITV.

 

When my tps sensor went bad, at start up my rpm's would fluctuate bad, went from 3k to 1k for about 15 seconds and almost stalled til it started idling at 2k.

 

vacc vacc vacccc!!!!!!!!!

just happen to me.

 

tps, cold start valve, iacv

what year and model civic man, and at what temp does this occur, like when its warmed up does it continue or does it stop?

 

more than likely it is the idle air control valve or iacv as people above stated. this is a common problem on our cars. is your check engine light on? also could be the fast idle thermal valve or fitv. you can try to clean both but this does not always work. on the idle air control valve, on the back of the intake it has one electrical plug going to it and is mounted by two 10mm bolts, and has 2 coolant hoses running to it. remove it and clean the inside of it out with carb cleaner or something, there are two holes you can spray the stuff into, after that, make sure you spray a lil lube wd40 or somthing because carb cleaner will dry out the rubber boot inside and it will start to crack....as for the fitv, its under the throttle body and i believe is mounted by 3 10mm bolts, and has one coolant hose running to it, on the opposite side of the coolant hose there is a plate with two screw heads or i believe 7mm or 8mm bolts, take them off and you can clean it the same way or try to adjust it by spinning the white plastic piece....also, you can adjust your idle by a flathead screw on the upper side of the throttlebody itself...goodluck and keep us posted so we can help you determine the problem

 

i dont know.. a buddy just ask me this question cuz he was looking to buy this 1 car.... thx for all the answer..

 

good luck then man, if u still need help keep asking

 

yeah.. thx for all the respond