Thread: Motor misfire. Check Engine Light

I got a check engine light the other day and noticed a small vibration sputter in the engine and had it looked at. The diagnostic code was for a Misfire in cylindar 3. So I asked what could cause this, they said either there is a spark plug or wire malfuction, clogged fuel filter or a Fuel Injector problem. I changed the front three spark plugs and wires and still getting the same problem. I have not changed the fuel filter as I know nothing about it and can't even begin with a fuel injector. Could it be a bad coil? anyone?

maybe the coil, just switch that coil with another one and see if the misfire moves to that cylinder

What year is the car? Mileage? Mods? How old are your plug wires?

My bet is wires. WIREZ.

Always do all 6 and new wires at the same time...why skimp? That's like buying one front tire...then waiting for the other to go bad.

Well I changed the front 3 wires and plugs, since the cylindar was in 3, I figured I could that and see, but still was not the problem, so I am looking into getting the Coil tested. When all is said and repaired, I will have the back 3 done by someone more intellectual than I. If it is not the Coil, I am thinking Fuel Injector, but I always use Lucas in the gas, so I am not leaning that way.

Originally Posted by GeosGP

What year is the car? Mileage? Mods? How old are your plug wires?

2001 GT with 105000 miles on it. I can't honestly remember ever changing the wires or the plugs. Do wires that you buy have the numbers on them? The wires have the numbers, but I will change both wires and plugs. No Mods.

Ummm...ya.

The back three are the same as the front 3 you know...and you don't have to number them...all you do is take 1 old one off...match it up to a new one that is the same size...remove plug...install new plug after checking for correct gap...then install wire. Repeat on the other 5 cylinders. Only one that really sucks is #4 because it is in the middle on the rear bank with the o2 sensor in the way...but...as long as you wear gloves you won't walk away bloody.

Psst..that's #6 with the O2 behind it. Friggin W bodies.

A more intellectual person than you, won't be any better at putting an arm down behind the motor and changing the plugs than you would be. Get up the courage and go do it. One at a time and you'll have it done with a little perserverance. Our cars are actually very easy to change plugs on when compared to other cars.

Pull the plug wire off the post for coil #3, start the car. Do you see a big spark jumping around? If so, it's not the coil. That's a good little test, that's quick and easy.