hey everyone i was just wondering if you could manually adjust your idle. my car runs a little rough when its in gear idling but is smooth when its in neutral. i changed my plugs to iridium. and i think but not sure if it started after. i was going to gap them but everyone told not to they should come gapped or else u will chip the iridium off.

 

No. You need to have a tuner adjust the idle speed using software to reprogram the ECU.

 

Check that the plug wires have "snapped into place" on the spark plugs.

Any codes? Clear codes - drive the car -recheck for codes. Post them.


Below may or may not help. (Maybe in the future)

Idle Learn Procedure
Anytime the powertrain control module (PCM) or the battery is disconnected, the PCM loses power, or the PCM is reprogrammed, the PCMs learned idle position is lost. The engine idle is unstable when the learned idle position is lost.

Perform the following procedure in order to return the learned idle to the correct position:

Automatic Transmission

Turn OFF the ignition.
Restore the PCM battery feed.
Turn OFF the A/C controls.
Set the parking brake and block the drive wheels.
Start the engine.
Ensure that the engine coolant temperature is more than 80°C (176°F).
Shift the transmission into Drive.
Allow the engine to idle for 5 minutes.
Shift the transmission into Park.
Allow the engine to idle for 5 minutes.
Turn OFF the engine for 30 seconds.

Manual Transmission

Turn OFF the ignition.
Restore the PCM battery feed.
Turn OFF the A/C controls.
Set the parking brake and block the drive wheels.
Place the transmission in Neutral.
Start the engine.
Ensure that the engine coolant temperature is more than 80°C (176°F).
Allow the engine to idle for 5 minutes.
Turn OFF the engine for 30 seconds.

 

Your Idle is PCM controlled and the only way to change it is with tuning. If your car is STOCK or very close to it, there should be ZERO reason to change the idle speed!!!

If your idle speed is a problem, there are several things that you need to check/repair.

The air tract between the MAF and the TB needs to be 100% air tight! If any un-metered air is entering the intake tract, the engine will idle rough. Check EVERY connection between the TB and MAF and all the vacuum line connections on the TB and intake. Especially the PCV connection and pluming. They have been well known to dry rot and leak vacuum. Ask me how I know. Same exact symptoms you have!!!

Spark plug wires!! Make SURE that there properly and tightly connected to the plug and coil. If you are un-sure if there good,, remove them and read them with an OHM Meter. The OEM wires should read 250-750 ohms end to end and the rubber boots should be in very good condition.

The coil end of the wire should positively snap into the coil connection. Make sure that the mechanical connection inside the boots are NOT corrodeed or damaged and not pushed too far into the boots!! They should be located near the end of the coil boot to properly connect to the coil connection!

If you ever need new wires, get the GM Performance RED Wires that Gene Culley sells. www.gmpartshouse.com There the best wires for the money and are the best quality out there.

BC

 

ok. ya i just changed plugs and wires about 4 months ago. so ill check all vaccum lines. thank you