Misfiring...

[gamellott]

I've recently developed a bad misfire which appears to pop up as a heat dependent issue. When COLD, Cold, cold, it runs perfectly. After it's heated up (Usually), It misfires on the #4 cylinder consistently. There is spark. I have no real reason to believe it's due to a failed injector, in part because it's rebuilt one that I put in a couple of weeks ago. The ECU seems to think there is no problem with anything.

 

When cold, the ECU flags the Knock Sensor, and Coolant Temperature Sensor (Not sure if that's normal, but they are 30 years old...). Once it's heated up, nothing, nada...

 

Aside from the Cap, Rotor, and wires, is there something else that the computer doesn't pick up that could cause something like this?

 

Would it be worth it to go in after the injector on #4 with a NEW one vs rebuilt?

 

Tune up parts are on order, so I should be able to rule those out quickly....  I say they're all relatively new, but it has been a hot minute since I swapped them out.... like nearly 10 years I think...