99 chevy lumina with code p0401

99 chevy lumina 3.1L 95,000+

service engine light on...code p0401...low egr flow.

tried another egr valve from junkyard...no change. exhaust tube has pressure and intake port seems to have good vacuum. if you reset the computer the light will come on again after about 1 mile. All the wires/hoses/lines look good.

...also,occasionally (usually when cold) the engine will idle way too high in drive...like 1500 to 2000 rpms (or higher in park!). recently ,on the expressway,I was going a steady 65mph without touching the gas! (no the cruise was not on!) If you pull over and wait a few seconds then restart the car it will idle and drive normally again.

I dont have the money to replace one thing after another 'til I fix it...and I for sure dont have the money to PAY somebody to try one thing after another,either!

my inspection is already overdue now and I'm getting frustrated and desperate!