My well maintained( gets reg tune ups and oil changes )..Mil keps poping up od2 reads cylinder 6 misfire...A tune should not be necessary ,,Whats the next step ..Changing the coil?? and what does that cost me ??
Frustrated in Jersey, Ben
Dear Frustrated,
Was the MIL blinking or on solid? If it was blinking, the system detected at least 1 misfire every 200 engine revolutions and there is the possibility that the catalyst will be ruined. If it is on solid, then it needs to detect a misfire every 1,000 revolutions on 2 trips.
The factory service manual has a long list of possible causes, starting with the ignition system. For starters, when the tune-up was done, were original Toyota platinum-tipped spark plugs used? If not, then that is a likely cause. Start by using OEM plugs.
Check for spark by pulling the coil and spark plug, inserting the spark plug in the coil, and crank the engine to check for spark.
After that, you will need an oscilloscope to check the injector firing pattern and a multi meter and factory service manual to check everything else.
Good luck!
Dear Frustrated,
My '95 Avalon had a misfire code after the spark plugs were changed. The dealer wanted to 'try' a new igniter ($700?). The problem was a loose connection on top of one of the coils - fault of the mechanic.
So my advice is to take off the plastic engine cover & make sure the wires going to the coils are connected securely. Doesn't cost anything but time.
TomC
It could be lots of things in the fuel injection or ignition systems. Recently I had a six cylinder Mitsubishi that would set a random misfire code for cylinder 6. Ultimately we traced the problem to a burned exhaust valve on that cylinder. How many miles on your Avalon? Have you had the valve clearances inspected and adjusted per the maintenance schedule? A tight exhaust vale (too little clearance) can burn. This affects the compression on that cylinder. Lower compression on a single cylinder makes that cylinder less effective than the others. And even though the fuel injectors and ignition system might be performing perfectly, the difference in performance of this one cylinder will set the random misfire code. Hopefully this is not your problem. You can rule it out with a compression test.
Ed
Changing the coil?? Yes.
and what does that cost me ??
I don't know what they cost, but they're easy to replace.
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