17663/P1255 - Ross-Tech Wiki
A bad coolant sensor; can cause a rough idle and hard start in the morning (when cold). Go ahead; fix that problem, that way you can eliminate that variable out of your troubleshooting process.
The miss fire; maybe a bad coil pack or other issues (wires, wiring, plugs, fuel, etc): please post ALL the codes that you pulled and we can try to help, further. Many here with the 2.0L; seem to have problems with the coil pack having hairline cracks. Spraying with water; to see if that affects how it runs, is one technique people have mentioned (to confirm if pack is cracked). What scanner or software (e.g. VCDS) are you using; it sounds like you do not have access to one (e.g. you had it scanned at Advance Auto)?
A bad coolant sensor; can cause a rough idle and hard start in the morning (when cold). Go ahead; fix that problem, that way you can eliminate that variable out of your troubleshooting process.
The miss fire; maybe a bad coil pack or other issues (wires, wiring, plugs, fuel, etc): please post ALL the codes that you pulled and we can try to help, further. Many here with the 2.0L; seem to have problems with the coil pack having hairline cracks. Spraying with water; to see if that affects how it runs, is one technique people have mentioned (to confirm if pack is cracked). What scanner or software (e.g. VCDS) are you using; it sounds like you do not have access to one (e.g. you had it scanned at Advance Auto)?