Car Running Rich, How to fix?
I think that my car may be running rich.
If I drive it for 30 minutes or more in warmer weather, the idle and engine firing starts to act funny. If you turn the car off and come back to within a short period the car seems as it doesn't want to run in lower gearing and at idle. Also driving at 20MPH in 1st and 2nd the car misfires really badly. Also in 5th at highway speeds the car will misfire slightly if traveling up a hill. The car never has up and down idling. The ideling acts as the car doesn’t want to run, or the engine is not firing as normal.
I have pitch-black exhaust residue on my tailpipe and back bumper.
How does one diagnose a car running rich? What causes the car to run rich?
What needs fixing? Do the above symptoms sound like another problem I should look into?
Thanks