after driving approx. 10 miles engine starts to miss and transmission shifts on 2001 Chevrolet Blazer

down and gas peddle feels soft, have been told it may be temp sensor is faulty what advice can u give me also no check engine lite comes on had it scaned and showed #4 piston miss fire replaced plug and plug wire still does same thing, has 3000 miles on remanufactured long block

Asked by for the 2001 Chevrolet Blazer
Code P0304 again?