I have a 99 pontiac grand am i ran the obd 2 on it and it keeps coming up multiple cylinder misfire. i have replaced the spark plugs, the coils, the o2 sensor,fuel injectors,the boots, crankshaft position sensor,catalytic converter,fuel filter,the tps,idle air control and amongst other things can you please help me
An expert who has achieved level 2 by getting 100 points
An expert who has answered 20 questions.
An expert that has over 10 points.
An expert whose answer got voted for 2 times.
Re: cylinder 3 misfire
Make sure you're using the recommended spark plugs. When my car did that, I had put Bosch Platinum Plus-4 plugs in and got that same problem. Turns out the plugs are too hot and cause it to fire prematurely and kick the misfire code.
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need. goodluck!
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Misfiring can be cause by ignition coil,spark plugs,wires,engine valve,cylinder compression,
if it's a quad four then crack around the ignition coil. there is 2 coils like 1-4 coil and 2-3 coil
first check spark plug color or foul of gaz
hope it help
A misfire doesn't always have to be ignition... it's just the most common cause. Faulty or plugged injector, low compression. You need to check fuel pressure and test the fuel injector flow. Then check compression. If you don't have tools for these tests, take it to someone who does. Testing is much cheaper than throwing parts at the problem.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
The Specific code "P0303" is stating that the Third Cylinder or Cylinder number 3 Is mis-firing, thanks to all that you have done this has narrowed it down to two "confirmed" possible problems;
The first is that the Exhaust VALVE itself may be "Burned" and the Second may be a Poor condition or "Faulty" Catalytic converter(s).
This is only a possible cause but please keep in mind that on some certain models (not too sure about this specific model) there are multiple O2 Sensors located in different spots. (usually in or next to the preliminary and primary catalytic converts)
Also one of my experiences lead me to beleive that the Ignition Control Module (ICM) may be faulty causing the injector to not provide proper Fuel to the Cylinder.which will more often than not cause the computer chip to sense the misfiring as opposed to the bad signal from the ICM.