Transmission concerns? or other?

I have 2002 Lincoln LS V8 (automatic) with 75000 miles, 29000 of which I have put on it. I am a novice in car repair concerns. I have recently had a problem when driving. The car is hesitating, and jerking slightly but noticably when accelerating, and accelerating after slowing down. It sometimes shakes softly when idling in gear and occasionally in park. I primarily drive in D5. I wonder whether it is a fuel injection problem. Perhaps the intake system needs to be cleaned. The problem may also be the transmission, I assume. Hopefully it is as simple as spark plugs. I am wondering whether any other owners/drivers have had similar problems and how it was most successfully and economically resolved. I will have to take it to the dealer no later than the weekend of Jan 30-Feb 1, 2009. All responses are certainly appreciated. More timely responses will be most helpful. I will report my findings from the repair shop as well as the successful remedy along with cost. Thank you.

Have the car scanned for trouble codes first.

Your car uses electronic controls for the engine, transmission, instrument cluster and other functions. In particular, it uses the OBDII system.

See here for more info:
http://en.wikipedia.org/wiki/OBDII

The electronics have a limited ability to diagnose and report on problems they find in the car. Usually a 'check engine' light or similar will come on, telling you that the electronics have found some problems and you or your mechanic need to fix them.

Usually the codes require some interpretation in order to understand what needs repair.
This site can give you more info or you can list the codes in this forum and we will try to help.
http://www.obd-codes.com/

Welcome to the forum!

The symptoms you describe sound pretty much exactly like the misfires due to leaking valve cover spark plug well seals (valve cover gasket set) that is extremely common. You will find many more details by using the excellent "Search this forum" feature from the Lincoln LS main page.

As MagicRat suggested, having the diagnostic codes scanned should help confirm that you are experiencing a misfire. Many of the chain auto parts stores will scan the codes at no charge. The car probably has some array of P030x codes where x would be the cylinder number with the misfire. Don't let the parts store sell you spark plugs though with the idea that will fix it.

-Rod

Thanks it was the valve cover gaskets, the ignition coils and the spark plugs.