Used Chevron Techron fuel system cleaner on the advice of a friend to try to take care of a couple of problems: 1) engine felt like it was going to stall out when in Drive and "shuddered", and 2) when accelerating in 2nd and 3rd gear (automatic trans), car would "miss", i.e., acceleration was very choppy. Problem 1) was almost immediately solved, Problem 2) is still there, but I've only driven the car a few miles. How long before I would see improvement? Any other suggestions? Thanks in advance.
Rich Nelson