2001 Pontiac Bonneville cost to fix misfire

I’m looking to buy this car and the people that are selling it said they replaced the spark plugs and found it may be the wires, causing it to miss fire, so the question is

(1) what could it cost to fix (2) what other things could this be (3) how much would it approxmently cost me to fix it here is the vin if that helps.

Answer: The engine misfire on the 3800 v6 engine is usually just bad spark plug wires. The rears are the most common to fail. Especially #5 on rear drivers side. Spray them down with water while the car is running and it will usually cause the spark to jump and you can actually hear or see it. Spark plug wire set would cost about $65 plus labor.

Other possibilities are a stuck fuel injector or bad ignition coil. The top of the coil would have corrosion on it if were bad.

See this link for a picture of ignition coil causing misfire. Ignition coils can cost about $80.

Other that that, if the misfire is on several cylinders, and only when trying to accelerate at highway speeds, a plugged catalytic converter could be the problem. This would be a much more expensive repair. Depending on what shop you go to, cost can be anywhere from $400 – $800.