Ok I have a 97 Civic ex with a D16Y8 VTEC and when you rev it up to 1.5 RPM it will surg. but if you rev it up pass that it sounds fine. Also while driving when you let off he pedal it kinda jerks the car and also the same when you give it gas again. My check Engine light is throwing a code for the IACV and I have took it off and cleaned it. Also the other day I just changed the whole intake manifold and distributor hoping it would be something between them 2. and still did not fix it. So I am clueless now...please help me somebody if you can...Thanks!

 

When I had this problem it turned out the throttle plate adjustment screw had manage to screw itself in slightly. The problem I had was that it had a high (1100 RPM) idle and would keep throwing the IACV code and would jerk like you stated. Basically it was keeping the IACV from doing its job and so it would a CEL for the IACV not functioning correctly. Are you sure the throttle cable isn't binding up or something? What's the car idle at?

 

I have messed with that screw before..I could take it almost all the way or all the way in and would not change a whole lot at all. Almost everything time I let off the gas to slow down it will idle diff. everytime, and I was wondering about the throttle being twisted or binded like you say.

 

are you still throwing the iacv light? if so you need to start there...fix the problem causing the iacv code...you may need to bite the bullet and replace the iacv...I'm not sure if that motor has a fast idle valve as well...

does it surge at idle? if it surges at idle, try this trick

remove the intake tube, look inside the throttle body...you should see two ports before the throttle plate...start the motor with the intake tube off, and block off one of the ports with the your finger, if the motor stalls, start it up again and block the other port, if the blocking one of the ports causes the car to idle normally then you have found your problem...you should be able to tell which component needs replacing by which port fixed the idle

the really really ghetto way of fixing this is to block off the port with silicone or urethane...really ghetto and not recommended but it will work

 

Yes it is still throwing the code...it does not surge at idle...just at 1.5 RPM but it does idle all weird usually always really low. Now by doing that trick...will that help me tell if the IACV is whats causing this?

 

Also I have noticed is that indstead of a normal car on a cold start it should idle a little high at first until warm and them idle down...my car is the other way around...it will idle really really low at cold start if idle at all...sometimes I have to sit there and give it gas for a little bit just to get it to idle.

 

Im not sure off the top of my head if that motor has a iacv and a fast idle valve or not, so the only other thing I can think of for you to try would be to unplug the iacv and see what happens

you'll get a check engine light for the iacv being disconnected, but if unplugging it "fixes" your problem at 1.5k then replace the iacv

 

Yes it does have a IACV but I'm not for sure what a fast idle is and dont know if it has one.

 

Bump.