I just got a 91 Legacy with an NA EJ22. It's been getting poor mileage and something I just discovered is that if I fast idle at 2000-2500rpm for a few seconds it will suddenly drop in RPM along with increased vibration. When I let off the gas at this point, it shudders and CEL comes on.
I've been able to narrow it down to cylinder one by invoking a misfire by fast idling, then disconnecting injectors one by one.
During the misfire, removing anything but cyl 1 causes further vibration but removing cyl 1(psgr side front) doesn't make any difference, so I've determined that this is the misfiring cylinder.
When I listen by the tail pipe at normal idle, something sounds a miss and I can smell that smell you get after using outdoor power equipment in my hair.
If I have the auto tranny in gear, I can't get it to misfire/misfire enough to be noticeable.
There's no drivability issues so far, but perhaps this is why I'm gettin 15city/18 hwy
new air filter
oil change (as if this makes any difference)
new spark plugs
Seafoamed through throttle body induction using Seafoam spray
Cleaned PCV valve, throttle body and MAF
I believe fuel filter is fine as there's no hesitation under heavy acceleration when fuel flow is the greatest.
I wanted to swap out injectors to see if problem follows it, but I couldn't figure out how to get them out
What do I check now?