nieces 2006 Monte Carlo is bucking and stalling,where do I begin to diagnose?

well, let's go simple, Joe....fuel, air, spark, timing....valve timing.....just begins to buck and stall as if some devil keeps switching the fuel pump on and off...or some devil keeps disconnecting the ignition again and again? I'm going to have to research what kind of ignition you have but I'm thinking twin coil-packs....you could check the OHMS from hot to ground (with the hot lead disconnected) on each coil pack to see if they are the same resistance...that'd be one thing that you could do....check the coil packs for leak to ground.....that's a start and costs nothin~... that's one item(s)~

How old is your battery, 'cause I'm inclined to believe that an undervoltage condition is causing the ignition relay to buckNbounce and make intermittent contact....your battery should be newer than five..(I'll explain why later) get a NEW battery so that we've got solid 12.5 volts and at least 30 continuous amps duty....for a start~ ....okay if we were going to test anything it'd have to be with the thing bouncin' down the road, or will it occur while stationary?,,,,,this is important because things get jostled loose and you don't notice them...like the battery hold down, leading to a fire (happened to yours truly last week)~ so at the garage does this happen, or only bouncin' down the road?~

might be as simple as a motor mount causing the high-tension to get too close to the hood or firewall....damn, seen that a dozen times~

keep me guessin' Joe, this is getting to be fun...until me wife comes back from the store~

https://www.google.com/#q=+2006+Monte+Carlo+motor+mount______ okay, with a floorjack and woodblock, you're gonna open the hood and jack up the motor...when you see the rubber has been shot a long time...you'll know it's time to replace the motor mount~

and joe after all that ,maybe in a month or two, check for high tension spark loss especially if occurs under load like roy says!

this is of course a guess of the highest order....could wait 'till nightfall and watch for the sparks....you might just douse all high tension wires in WD-40 and the ignition problem will vanish~

Joseph K Gandhi stepped out for some coffee...apparently~....possible arguements with the girl..what do you think 7jimmy7?~

....apparently our friend Mr. Mark K, helpful, esq. has left the building as well~

whos arguing? yours was to stop by you said, she really cares , that's nice , the painting is fantastic straight up for sure! yours or hers?