I have searched a lot of threads and not come across this problem mentioned by anyone else. I have 93 Civic DX 1.5. Car starts fine fast idles until warm and runs smooth in P or N. As soon as I put it gear it sputters and wants to die but doesn't. I barely touch the gas and everything is fine. Car drives fine, idles normal when sitting in gear in traffic ect. Just wants to die everytime I shift it in to gear from P or N until I give it a touch on the pedal, Any ideas?

 

clan the idle air control valve and see if that helps also check for vacuum leaks.

 

I suppose that could be an issue. Might have gone bad but it was removed and cleaned a couple months ago along with every other valve and sensor that has anything to do with the idle when I was chasing a hunting idle issue. Turned out to be a bad ECU. Ran fine once the ECU was replaced and now this just started.

 

Check that the IACV is getting power. One wire is battery voltage all the time the key is on. The other wire is pulled to ground by the ECU to open the valve. The valve coil should measure about 15 ohms. If its open circuit you need a new valve. (That should throw a code 14 though. I assume there are no ECU codes set since you didn't mention any.)

Beware that the IACV, IAT sensor, and canister purge solenoid all have the same type of 2-wire plug and it is possible to mix them up and have things plugged in wrong.

If unplugging the IACV causes the engine to stall in Park, open the air valve screw on the top of the throttle body some (you may want to unscrew it all the way and clean out the passage first). Set the screw for a slow idle, but still running (450 rpm) with the IACV unplugged. Do not mess with the throttle plate stop screw, it is not used to adjust the idle.

 

 

Ok guys, appreciate the help but maybe I'm not doing a good job of explaining the problem. It's not exactley an idle issue. It's more of a sputtering when shifted from P to D. As soon as I give it a little gas it corrects itself and runs fine after that. it doesn't idle high, low or hunt and I have watched the ETCG stuff and read about every thread I can find and none of these really match the symptoms I'm having. Any other ideas? If not thanks for trying to help.

 

When you shift to drive there is drag on the engine from the transmission, the engine then needs more air to maintain the same rpm, which is the purpose of the IACV.

Edit: for runnability issues you should also double-check the ignition timing. Timing also affects the idle speed, the ECU varies it dynamically as a method that is faster than the IACV.

 

ok, got it. I will follow your advice and see if I get this figured out.

Thanks!