I was driving a couple of nights ago when all of the sudden, while accelerating normally for in-town driving, my '03 TL-P started sputtering, shuddering, and flashing the CEL. Very rough idle, slightly less rough acceleration, but it will go without hesitating. No obvious sounds of mechanical damage, oil looks dirty but normal. Using a paper clip I pulled codes 701-706. I limped it back home and changed all of the spark plugs, which are all old, but otherwise unremarkable. Heavy smell of unburned gas coming from rear head when I pulled those plugs. Nothing changed. While looking for vacuum leaks, I noticed that the EVAP purge solenoid was making a series of loud clicks after about 20 seconds of starting the engine cold. I'm also not sure if it could be related, but I'm getting ABS speed FR speed sensor and motor stuck on errors. I've scoured the internet for info, the main culprits I'm looking at are fuel pump/injectors, IACV valve, timing belt, and ECU. Unfortunately, I'm sick with the flu (MC Murphy in full effect) and I can't do much out in the cold... so I'm looking for any input that might help me get back on the road before Christmas. Thanks.

 

First thing to check would be the ignition coils. Do a cylinder power balance test by unplugging the coils one at a time until you find one that does not cause a change in RPM. If you find a cylinder that isn't firing, swap its coil with another to confirm that the ignition coil is the issue.

 

This was my initial suspicion but the codes not isolating it to one cylinder threw me off. I actually tried that on my own accord, then saw this. That was indeed the issue. I appreciate the help.