A malfunctioning EGR valve can cause:
Rough idle or stalls on deceleration.
Hesitation or surge.
Abnormally low power at wide-open throttle.
Check the vacuum lines and vacuum source if applicable.
Check the electrical connection and valve function. Was the EGR port cleaned?
Other causes of stalling/surging/fluctuating idle could be.
low battery voltage (battery or bad cables)
Bad wiring or loose connections (Check IAC and TPS)
Failing ignition switch.
Failing ignition module.
Fuel contamination/quality in gas tank or fuel lines.
Clogged fuel filter.
Weak fuel pressure (Check fuel pressure regulator and fuel pump).
Fuel pump inertia switch.
Dirty air filter.
Engine coolant level.
Defective thermostat and/or fan switch.
Clogged PCV valve.
EGR valve stuck open.
Exhaust System Blockage.
Poor camshaft timing and cylinder compression.
Just looks like a lot to check. :)
I would also consider cleaning the throttle body, IAC valve and it's port, and using some fuel injector cleaner.
Sometime tapping on the TPS with a srewdriver handle will show up a bad TPS by making the idle fluctuate.
Good hunting and let us know. :Twisted:
Saturday, February 25th, 2006 AT 9:00 PM