check your spark plugs your mechanic ripped you off check your magneto or sparplugs mostlikely case

something mite be wrong with timing i herd something like that in a camry

Right after your engine air filter is your MAF (mass air flow) sensor.  There may or may not be a screen in front of it, but there will be a wire running across the middle of the opening.  Spray that down with either Brake Clean, or Carb/Choke Clean and see if that helps.

If there is any dirt, oil, water on the MAF it will cause your issue and not set a code.  What you had going on with the EGR system was probably not related to this issue, but would affect your emissions.  

I owned an crown vic interceptor which had the exact problem.  It would "stumble" sometimes at idle or like you said, pulling out.  Normally I would gas it to overcome the stumbling up to 10mph or so.  I did what the others said, changed the spark plugs, plug wires, cleaned the MAF, changed the EGR, everything.  I still had the problem.  After further inspection of the throttle body, it seemed the catch where the diaphragm would stop the valve travel was gapped too much.  I placed a small rubber cap on the stop, adding approx 1/32, then the problem stopped.  Without applying gas pedal pressure the throttle body "should"  maintain proper idle.  For some reason our cars were notorious for stumbling.  I know it sounds like jerry rigging but its effective.  But I always suspected one other thing, the coil packs.  You have two of them, and I have heard sometimes they lose idle charge capacity which would produce improper spark, thus also creating the stumbling.  It is an easy install at 40.00 a piece and also replace the small side capaciters attached to them.  Hope this helps and respond to me if you need further help.