Jerking Issue

I have a Mazda MVP 2003 with approximately 140,000 miles. While driving down the interstate at a constant speed it jerked twice but didn't do it again as I drove the final 3 miles to my destination. After spending about an hour there, started the car up and it idled fine but when I put it in reverse it idled very rough but did not die. I then put it back in park and then back in reverse and it was OK. I then proceeded to drive home on the interstate, but when I got into town and came to a stop sign it jerked again.

I'm not sure if it related but for the last couple weeks the engine light has been on and gives the code P0443, which deals with the EVAP control system purge value circuit.

Does anyone have any ideas what could be causing the jerking?:mad:

Start by checking the evap system. Seems like the place to start. Clogged or leaking hoses, canister, pcv valve?. Not sure what these cars have. I just picked up a 05 so just checking the list, but haven't got my factory manuals yet or had a real good look under the hood, so I'm not real familiar yet.

What about tune up lately? bad plug wires, fuel filter, plugs?

Not much help but places to start.

That engine as an individual coil for each cylinder, would cause jerking motion... was the check engine ligth flashing? Also at the back of the engine, in the middle of the surge tank is where the PCV hose attaches, they have been know to crack at the elbow there, causing engine to run rough...