When the engine is cold, it has a rough start and feels like it's gonna stall out, it also blows out black smoke, I recently changed the spark plugs, oil and air filter. I took out one of the spark plugs and 1st, 2nd and 3rd where lightly covered in oil, the 4th one was just fine. What could be the issue?
If the spark plugs are coated in oil, that can cause a rough cold start or idle. The engine is burning oil in cylinders 1, 2, and 3. The most typical cause is from worn valve guides. The intake and exhaust valves move up and down within the valve guides. When they wear, oil can get past the valve stems, coating the spark plugs. Other causes can be worn piston rings and/or scored cylinder walls. A complete compression test should be done to determine which is the cause. Worn valve guides can be remedied by rebuilding/replacing the cylinder head. Worn piston rings or scored cylinder walls may require an engine rebuild/replacement. Have a trained technician inspect the starting issue in order have the right repairs made.
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