project250

Greetings all, looking for more info regarding a misfire on a sc400 when idling and when cruising at about 40mph, run's fine on the highway. I've noticed the misfire is most apparent while the motor is warming up, first 20s or so of idling is fine, and after the engine is up to temp the misfire is still there but much less apparent.

What I have replaced so far, with no change:
-plugs
-wires
-rotors
-caps

Over the past couple months the misfire has gotten slowly worse. What would be my next step? I've found through searching that sometimes the ECU goes bad, would that cause a check engine light? How would you be able to tell if the ECU needs replacing?

Those of you that have had misfires like this in the past what was the solution?

Thanks in advance for all your help

JaySc300

My missing issue was a stuck fuel injector. Pulled plugs and found one carbed up. Tapped injector with hammer and socket extension slighly and with car running and its perfect.