Anyone ever hear of problem with frost buildup on spark plugs?

Heh. "Frost on the spark plugs..." I gotta remember that one. If the engine cranks OK for awhile and then starts and runs OK (high idle, etc.), Check the intake air temperature sensor. It may be out of it's limits. This sensor helps the engine's control computer calculate the best injector pulse width for cold starting. If the car doesn't crank fast enough to fire the engine-change to a lighter grade engine oil. (Less load on the starter-it'll turn faster when it's real cold out. If the car cranks OK, starts OK but runs rough (misfires, smells like raw fuel out the exhaust) for a bit-replace the spark plugs and plug wires. Moisture will short leaky plug wires to ground or an adjacent cylinder's wire causing misfires. Spark plug wires and plug boots in proper condition pretty much seal out any kind of moisture. 'Frost on the plugs, indeed...'

no my family lived in NE PA for 36 years and never i have brought my battery in at -21f but never a plug problem if the spark plug wires are securely fastened to the plug there should be no moisture to create frost I'm thinking more a water in gas problem maybe add some dry gas additive you can get this at any place that sells car stuff

no

You are right the frost on the plugs is a bogus excuse because they don't actually no what is wrong. If you have had the spark plugs changed(calls for every 30,000 mi) and the wires are in good shape, I would look towards the battery or cables. PT's are notorious for build up on the terminals and cables if cleaning the terminals doesn't fix it make sure if you have the battery tested it is a load test. If cleaning the terminals helps any parts store should have a battery terminal protector spray to keep the build up from coming back. Hard start is to often because of carbon build up in the engine. Because the carbon soaks up the first few injections of fuel.

No. The Chrysler ignition system can fire a spark plug in almost any condition, icing included. There's nothing special about this engine that would cause such a condition, and other cars can start right up: hell, my Geo Metro does. Find another service place, have them check the battery, its charging system, and the codes stored in the computer: if you've got problem with the ignition system (including 'frosted spark plugs') the computer will have recorded any misfires, including the cylinder in which it occurred.

I suspect you have a grounding issue somewhere in the ignition system check it for cracks or damage your expert missed

when the engine cools moisture can collect on the plugs that is if its on the outside if its on the electrodes -end in engine-you may have water in your fuel

Change plugs AND wires.

of course it could. when the engine cools down from being hot it produces condensaion or how ever you spell it and that would be a big problem in cold weather a block heater would probably help it.