crashnburninc

I am trying to diagnose a problem with my girl's civic. The car sometimes (not always) feels like its going to stall (it's an auto trans) and runs rough. the real problem is that sometimes the engine will rev itself when the driver is trying to slow down and you really have to stand on the brakes to stop the car. and to make matters even more hilarious once the car comes to a stop the driver has to either put the trans in neutral or hold down the brake hardcore to keep the car from going forward. The only thing she has done to the car is a cold air intake. When she took it to the shop the fault code said the problem was with emmisions? O2 sensor? dirty air filter? Im thinking that i'm going to do a full tune up on the car and hope the problem lies in either filters, plugs, wires, o2 sensor. Anyone have any input????

vtecpower1062

sounds like it could be her idle air control valve (iacv) going bad. When my iacv was going bad when I would be slowing down sometimes or at a stop the car would rev, basically surge by its self. It certanly sounds like she could have a bad iacv and its worth it to check it out to make sure its working ok.

JeffS

When sitting still and in park, does the idle surge up and down, or is it steady?

crashnburninc

i'll check the icv but i dont think that is it becuase the motor will run normally 80% of the time. And yes the car does SOMETIMES surge while in idle but not all the time. When the surging occurs it will surge when it first starts up at idle, while driving and while stopping. Only after clearing the fault codes or waiting for a while with the car turned off will the motor stop surging. the car has 90K miles.

BauleyCivic

What year is the car?

crashnburninc

99 civic dx

BauleyCivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crashnburninc &raquo;</TD></TR><TR><TD CLASS="quote">99 civic dx</TD></TR></TABLE>

Okay, that rules out the fast idle throttle valve because that car doesn't have one...I'd check out the idle air control valve on the back of the intake manifold.

crashnburninc

also for some reason the car will not shift out of park when the motor is surging...i have to press the safety release button to get it into drive...maybe becuase of the elevated revs?