About 6 months ago, I had some preventative maintenance done on my car that included oil change, plugs and wires. Within a week of running out of gas my car began "stumble" and idle rough. I ran injector cleaner through system and replaced fuel filter. The problem escalated to a new level when the check engine light began blinking. Trouble codes said multiple sensors needed replaced, and the no, 1 plug was misfiring. Plug was replaced..check engine light went off car ran great for about 10 minutes or maybe 10 miles. Now The "stumbling" is back as well as the "check engine" light. Could a sensor be responsible for this scenario ?

  • 1
    Is it oil-fouled or fuel fouled?
    – mikes
    Commented Apr 6, 2013 at 1:37
  • fuel fouled. Also the trouble codes indicated the MAP, 02, and 2 other sensors had issues.
    – Lori Bell
    Commented Apr 6, 2013 at 2:55

3 Answers 3


Since you have new plugs and wires you may have a bad coil. Of course one of the new parts may be bad, not unheard of but unlikely. If the fuel injected into the cylinder isn't burned it passes into the exhaust system where the O2 sensor sees a rich condition that is outside the normal parameters and sets a fault code. You need to see if that cylinder is getting spark. Remove the plug wire from the spark plug. Insert a screwdriver in the cable end. Holding the screwdriver handle place the blade of the screwdriver near some metal part of the engine while an assistant cranks the motor for a few seconds. You should be able to see a spark arc from the screwdriver to the metal. You will want to do this test while the engine is hot. It isn't uncommon for coils to work for a short time then fail when it gets hot.


In general, yes. OIL fouling of the spark would be the correct assumption. However in this particular motor, which is notorius for blown head gaskets and lower intake manifold gasket leaks, allowing coolant into the combustion chamber I would take a look at these first, and in order. 1. fuel pressure, this all started after you ran out of gas correct? you should have a vavle on the fuel rail, to hook up a pressure gage to. 30-40psi with regulator vacuum hose attached. 45-55psi with hose disconnected. 2. #1 fuel injector pulse, is it actually spaying fuel into the cylinder? causing no combustion. or is it leaking after shut down and fouling? ? is the connector loose? 3. COILPACK..... do you ever get PO305 code along with your PO301 code?

Also in general there are "oil Rings", to clarify these "rings" actually control the amount of oil they let by them to coat the cylinder wall for lubrication to reduce friction and heat. They dont seal. The cylinder wall wears to the point were they cant control the amount of oil anymore. The fix is the same tho.


The number one spark plug failure is caused by oil getting to the spark-plug through piston blow-by - this can be fixed with new rings / pistons (oversize for best performance)

  • This sounds plausible, but it would be nice to give OP some advice on checking whether this is the case. Is the plug/combustion chamber covered in oil? Commented Apr 6, 2013 at 1:40
  • in a normal engine the piston will have one if not more "oil rings" these are to keep oil from reaching the combustion chamber - when your motor starts smoking bad its because the oil is managing to slip by those rings and burn with the gas in your combustion chamber..
    – dashboard
    Commented Apr 6, 2013 at 1:44
  • Is that something feasible for a non-expert to fix? I would suspect having it done professionally is more expensive than buying a new engine... Commented Apr 6, 2013 at 3:12
  • Starting off by condemning internals is rather harsh. Some checks before rushing into tearing apart a motor would have been a much better starts.
    – cinelli
    Commented Apr 6, 2013 at 3:14
  • The main cause of bad spark plugs is exactly what i stated above - OIL - now it could be that the spark plug isn't getting enough voltage to make a very hot spark in which case you could look at replacing the rotary cap, coil, generator, etc...
    – dashboard
    Commented Apr 6, 2013 at 3:57

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