Help - 2014 FRS Rough Idle and Cylinder 4 Misfire
 

Hi All,
I'm trying to diagnose a problem with my car. From my log I'm getting very rough idle after startup, high misfires on cylinder 4, and shows injection mode 1.

When I rev and hold the engine at 2000 rpm, then 3000rpm, then 4000rpm it moves to injection mode 3 and there are no misfires. After idling back down it again misfires in mode 1 and is smooth in mode 2.

Does this mean that my port injector in cylinder 4 is bad or clogged? Here's a link to the data log.

https://datazap.me/u/frs2slow/frs-ro...0&data=7-18-32

Pulled and cleaned the injector, but still have the problem. I recently also replaced the coil packs and spark plugs as well. Thoughts?

what coil packs and spark plugs did you use?

Off the line racing coil packs (and adapter harness). Denso 3536 iridium plugs.

were the spark plugs purchased locally or online?

if locally, i suspect the coil packs/adapter harness.

if online, i suspect fraudulent plugs.

Thanks soundman. The spark plugs were purchased from local major brand auto store. I pulled the OTLR coil pack and put the oem coil pack back on. Idling well now with no misfires in the logs. I'm going to take her out for a spin and see if all stays well. If so, looks like I got a failed OTLR coil pack and/or harness.

yeah, unless you're heavily modded/tuned, keep the ignition system oem. aftermarket doesn't play nice without supporting stuff