2004 Savana Van with 4.3 L Vortec can't locate an egr valve Engine runs rough at idle and lacks power

Do a compression test. Maybe that motor needs major repair.

Yes the car won't run properly with a bad EGR valve and will use a lot more gas as well.

You must have an egr valve for this engine to work.Sounds like you are getting oil blow-by combustion causing carbon in the exhaust which may do due to a faulty crankcase ventilation valve, bad piston rings, etc. Whatever the cause, oil combustion produces the carbon, and you will need to fix that.

Spark Plugs have to be changed every 3 years
Front Oxygen Sensors changed every 100,000 miles
Can't have any Vacuum Leaks -- anywhere on the vehicle
Need to have it road tested with a Professional Scan Tool
& look at all data & get caught up on Preventative Maintenance
Very few people change motor oil 3 or 4 times a year, if at all,
and the Variable Cam Actuators fail, as a result,that & few other
things can cause rough running engine & resulting idle issues
It's well known that Ford COP Ignition Coils fail sometime in
every year of ownership

It sounds like a vacuum problem is keeping the EGR valve open causing the other sensors to read this and more fuel would be injected by the ECM. u may of gotten an egr code but the problem is not the valve itself.

Yes it could cause that. the EGR is near the rear of the engine, if it is leaking it will sizzle water when you touch it with wet fingers.

For rough idle issues and problem troubleshooting,go through the help links provided below :----- van idles rough?

http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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will not idle when cold?

http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html

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runs lean and idles rough?

http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

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Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

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Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

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Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

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Replace Idle air control valve?

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Test Idle Air Control (IAC) Valve?

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Idle Air Control (IAC) Valve operation?

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Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

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Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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This will help.

Thanks.

For rough idle issues and problem troubleshooting,go through the help links provided below :-----van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html---------will not idle when cold? http://technoanswers.blogspot.in/2012/02/ford-explorer-40-will-not-idle-when.html
----------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Engine stumbles coming off idle when warm? http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html
------------Erratic idle on car? http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html
----------Low idle when cold out side? http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html
---------Idle Air Control (IAC) Valve Replacing? http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html----------Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

------------
Car overheats and Air blows hot at idle? http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html
------While stop engine idles like cylinder missing? http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html
---------This will help.Thanks.

Rough idle is a very common problem on 4 cylinders, but I believe the 98 Regency has a 6 cylinder in it, right?

Sometimes the coil packs get iffy, and sometimes the EGR Valve gets a leak in it causing a rough idle.

When the accelerator pedal is depressed, it can change things so that the engine seems to run smoothly.

However, I would look for codes to see if anything intermittent is occurring in the engine that may need attention.

The OBD-I scanner can help to diagnose the problem, if anything is out of specifications on the engine in question.

The owner will have to find a technician that has such a scanner.

try cleaning the inside of the MAF sensor with CRC brand MAF cleaner, it is availiable at any auto parts store for around $5