The dealer finally fixed it. But it wasn't easy. They had the car for 10 days until they finally replaced the following for the #4 cylinder:
53021580AE (2) Springs
5135357AG Gasket Kit - Upper Engine
53032152AD Solenoid-Multiple Dispalcement
53021726BB Tappet - Hydraulic
oil, coolant, cleaners, etc....
Parts and labor = $1280
More details from tech: Here is some more detial from the work order: The actual tech doign the work wrote:
"Verified concern: found code P0304. Found Cy#4 misfire. I have already checked Comp, plugs, coil, and injector. Checked to make sure coil and injector were receciving signal. Was OK. Pulled intake manifold off, found fuel puddling on the back of the intake valve #4. Reinstalled manifold, removed injector, watched injector pulse while cranking, it appeared to have more pulse than injector #2, swapepd injectors, NO CHANGE, Called STAR, STAR advised to replace PCM, repalced and reprogrammed PCM, STILL MISFIRES, removed cyl head to inspect valves, had head sent out to measure guide wear, check valves and seats, ALL OK. Replaced both intake and exhaust valves, springs and stem seals, STILL MISFIRES. Called STAR again. They reccomend to replace MDS Soleniod and Lifters, removed soleniod and lifters to inspect, NO PROBLEMS FOUND, replaced lifters and soleniod. Per customer (info I found in this forum
) inspected overfill charcoal can, NO PROBELMS FOUND, reinstalled head and all drive OK. No more misfires."