Chrysler Repair: 2004 pt cruiser stutter., wd 40, chrysler vehicles

Question
would like to know why i've taken my car to chrysler to have my car fixed. told them my car shakes every time i come to a stop  it feels like the engine wants to turn off.had three diognostics done at chrysler they tell me the same thing over & over .its getting worst. please assist tell me where to start .did my 30,000 mile check up

Answer
Hi Irving,
I don't make any claims to be expert in post-2000 Chrysler vehicles, but I have one suggestion: the egr valve. When the engine drops back to idle speed from a higher rpm, that valve needs to self-close via internal spring action or the mixture will be too lean and cause missing or dieing. It is located near the throttle body intake bolted into a small pipe that runs from the exhaust manifold back to the intake area. It has a valve body that is bolted into the pipe, a round vacuum-operated actuator on the top and a flange in-between those two parts. Inside the flange you will see a rod with a circumferential slot, which is the valve stem. You can move the stem back and forth by means of the tip of a screwdriver inserted in the slot. A spring will try to close the valve. If the valve stem is cruddy it will bind up and not close by spring action. If that is the case, spray the valve stem where it enters the body with WD-40, then exercise the stem to fress up the action. If that was the issue, this will remedy your problem. Otherwise, tell me what the codes are and what they did about them. You can get a free code readout at most Autozone parts stores.
Roland