I have 1999 civic with 175k miles and have been having evap and missfire codes appearing (missfire code in cyl 1 & 3). From these codes what should I replace? I took it to a shop and they said everything is good (said evap system good and compression good all sides)? I have ran a cleaner through and a few bottles of heet through. Originally when I ran some heet through it cleared all codes for about 2 weeks, now it came back and hasn't shut off with same treatment. When I stop at stop lights the vehicle will shudder and almost feels as if it is going to die, attribute this to the missfire.
What should I start with or what is the problem?
I planned on replacing spark plugs, & wires... what else?