carbon covered spark plugs

[tunky]

Hi guys,

I have an 88 hb and last week starting acting funny. First the check engine light came on and it blink once meaning a problem with the oxigen sensor. The car didn't run strong anymore and it idle rough, like it wanted to turn off. I reseted the ECU three times and the check engine like still came on. So I replaced the Oxygen sensor.

Then, the car still idle rough and it was running weak. Also, replace the spark plugs and and when I remove them to check them, all of them were covered in carbon. And the exhaust smells really bad.

Please, post if you know what could be causing this. Thanks

[Marc-OS]

Did you check your timing?

[tunky]

I figured out what the problem was. The hose coming from the map sensor to the intake manifold had a crack. I couldn't see that before because the crack was facing the fire wall.