Diagnosing this problem

So, my car is having issues. When I am parked or stopped with my foot on the break, the RPM on my car goes way down, starts to shake, then dies. We called AutoZone, and they suggested to replace the fuel filter, so we did, which did nothing. We then called schucks, which suggested replacing the EGR valve, which still did nothing. What could be the problem?

Do the RPMs change if you release the brake pedal? If they do then there may be a vacuum leak in the brake booster.

If I push the break, it begins to shake and lowers the RPM to less than 500, when I release the brake pedal, the RPM stays lower and the car continues to shake until I push the gas.

We really need make,model,miles,trans type,any repair history.

2001 Ford Escape XLT. 3.0L, approx 140,000 mileage. Auto transmission. At 90,000 miles it had a tune up. It has had routine oil changes. We fixed the struts. We recently talked to schucks and AutoZone and replaced the fuel filter and EGR valve, and it didn’t fix anything.

Will the car start and idle normally IF YOU NEVER TOUCH THE BRAKE PEDAL?? If you set the parking brake and put it in gear (if it will allow you to) without stepping on the brake pedal, will it idle normally??

I am trying to see if the BRAKES have anything to do with this…

When I put it in park, it does the same thing tho.

When it is in park, it idles low, as if it’s going to die. When I don’t push the break and have it in gear, it acts like it’s going to die again. If I put the parking break and put it in gear, it does the same thing. It continues to idle very low or die until I push the gas.

Idle air control solenoid, throttle position sensor, dirty MAF or throttle body, vacuum leak.

I agree with the vacuum leak or Idle Air valve diagnosis.
One thing you should not do is rely on automotive technical advice from parts counter people; especially those at the chain type stores.

Now and then you will see a counter guy who is pretty sharp mechanically but it’s very very rare.

Is the Check Engine light on? If so, get the code read at the auto parts store for free.

Classic Ford Idle Air Bypass Valve problem.