Hyundai Repair: Car revs and bogs, spark plug wires, govoner

Question
This is a follow up question to yesterday's question which I have enclosed in the question. I looked for arcing signs on the spark plug wires but didn't see any. I drove the car on the highway for a while and it started bogging like it was not getting enough fuel then when I got off the the high way the egine continued to rev then idol down. I put some fuel injector-carb cleaner in the tank and it seemed to help. I changed my spark plugs also but it still bogged some after driving on the highway and reved a little. Do I have a govoner or some thing sticking? If so is there a really good addative you recommend I put in the tank. Could it be partly that my fuel filter is clogged? I also filled my tank with the highest octane gas. Thanks again.

("Subject   Check Engine Light

Question -
My engine check light has been staying on/flashing the last couple of days and my car has had a hard time starting, especially in the morning. I read here about the fuel filter location and want to change but you mentioned it may be other things. What are they,I want to do the repair myself if I can. I checked my gas cap tightness, I think that was the problem the first time but now I don't think it is.  Thank you.

Answer -
A flashing check engine light is a missfire. Not knowing what model you have I can't tell you much about what to check
Model? Year? Mileage?

More Info-
It's a 2002 Accent, 1.5 SOHC engine with 64,000 miles. The flashing is only some times. The check engine light stays on most of the time. It runs a little rough at start up then ok. Could the spark plugs be at least part of the problem?



Answer   Could be the spark plugs.  More frequently, the plug wires arc through the side to the spark plug tubes.  You'll want to give your ignition system a good check.  

Open your hood and remove the spark plug/plug wire cover.  Pull each of the wires off the plug and inspect the tubes for evidence of carbon (from arcing).  If you find any, that's a misfire source.  If you haven't found the soure yet, place each wire back down on the plug without snapping it all the way on.  Now start the car and check for arcing.  If you see none, gradually lift each wire one at a time off the about an inch and place it back.  You're looking for arcing when you do this.  The spark should jump out the end of the wire onto the plug or the plug tube.  If you see arcing at the coil or out the side of the wire, you've found a misfire source.  

You can also use this method to see which cylinder is misfiring if it's misfiring when you're checking it.  If you pull a wire up and the engine doesn't run rougher, that's the misfiring cylinder.  If you don't have any abnormal arcing, you can switch the spark plug with another cylinder.  If the misfire moves with the spark plug, the spark plug is the cause.  If it stays in the same cylinder, then you've got a compression or fuel injector issue.

Also check the porcelain of the spark plug for a vertical black carbon line.  If present, ignition fires down the outside of the porcelain along the carbon line instead of firing the spark plug.

Replace anything that's arcing where it shouldn't be.  I recommend using only factory plug wires.  If your spark plugs are worn or have more than 30,000 miles on them, they should be replaced.  You should replace them with a well-known quality brand such as NGK or Denso.")  

Answer
Is your check engine lamp still flashing?  If so, then you've still got a misfire you need to track down.  If you've eliminated ignition, then you need to check compression and injectors.  If you have it scanned for codes, you'll get at least one P030x code where x would be the number of the misfiring cylinder.  That'll help you know where to look.  If you cannot locate the cause of the misfire, you should have your car checked by a professional.  Driving your car while the check engine lamp is flashing will very likely damage your catalytic converter.

If your check engine lamp is now just on steady, you should have your car scanned for codes.  They will typically provide a hint as to the source of your problem.

It's entirely possible that you may have repaired the misfire, but, as I alluded above, your catalytic converter(s) may now be damaged and not allow enough exhaust flow for the vehicle to run normally.  This will cause worse power losses at higher rpm's.