Engine Performance problem

[z06man]

1999 Ford Explorer V8 All Wheel Drive Automatic 81000 miles

I have taken my explorer in multiple times for the same problem. In May of 2009 I was told my idle issues were due to a bad Idle Air Control Valve so it was replaced. The problem came up again last month and they said based on the error codes the Mass Airflow Sensor needed replacing. So that was replaced last month. The problem is still there so i went and bougth another Idle Air Control Valve and put it on. Still not fixed. When you start up the Explorer it idles rough down to 500 rpm and below almost dying when you give it gas it almost dies. Then while driving it sputters and you can put your foot into the gas it goes no where almost dying then all of a sudden the motor kicks in and lurches forward. This happens whether the car is cold or warm. What else could it be? My brother inlaws thinks it might be EGR. I do not know.

[shorod]

Has the check engine light ever come on? Have you checked for pending diagnostic codes?

It does sound like a vacuum leak which could be a loose intake air tubing (possibly not properly installed after replacing the MAF sensor), a vacuum hose, or an EGR valve. The EGR valve should be closed when the engine is at idle. If not, it is acting as a vacuum leak. It's not uncommon for the DPFE which controls the EGR to fail on this generation of Ford.

-Rod