EGR system is only used when engine is under load, like driving up hill or accelerating hard.
So EGR valve's vacuum hose should never have vacuum at idle.
Follow the EGR Valve's vacuum hose back to the EGR modulator(solenoid valve), it will have an electrical connector, the computer activates this valve only when engine is under load.
Unplug the electrical connector, start engine.
Check EGR valve hose for vacuum again, if it still has a vacuum replace EGR modulator, it is stuck open.
On the intake there will be a 2 wire IAT(intake air temp) sensor, gray/red and gray wire.
Computer uses this sensor to fine tune fuel/air mix, colder air is denser so needs more fuel added, warmer air less fuel.
In later models the IAT and MAF sensors were combined, 4 wire MAF, older and 6 wire MAF/IAT, newer.
Gray/red wire should have 5 volts, Gray wire should have less voltage, use a sewing pin to pierce a wire to test voltage.
Colder temp = higher voltage on Gray wire
Warmer temp = lower voltage on Gray wire