replaced bad coil pack and new coil not sparking car starts but runs rough engine light on blinks sometimes

Car started running rough while driving. tests revealed bad coil pack cyl 1&4. replaced coil still not firing now #6 not firing too. Car starts right up runs rough and even more rough when shift into drive or reverse engine light on and blinks when accellerator is pressed. Car has over 250000 miles but was rebuilt about 10 months ago. Car was operating fine and noticed gas milage began to decrease in last couple weeks this problem started 3days ago. Spark plugs and wires replaced about month ago. Would appreciate some direction to take troubleshooting or a diagnosis. Thank You.

My car

Experienced mechanics share their insights in answering this question :
Hello and thank you for your questions. If your engine was rebuilt about 10 months ago, the question is to determine if the management system has been installed as well. With the symptoms that you are having, it sounds like the coil packs are old and in need of replace. You replaced numbers 1 and 4 and now number 6 is not firing. I recommend replacing number 6, 2, 3, and 5. This will ensure that you have all 6 coil packs that are new.

Just because the coil packs are okay during a test doesn’t mean that they are functioning correctly. Coil packs on Buick vehicles from 1998 – 2005 last between 150,000 to 200,000 miles. I also recommend having your fuel injection system flushed. Unless you have new injectors, the old injectors could cause a cylinder to fail, even though it is working correctly. These symptoms can cause the engine to have a rough idle and rough running during conditions. If you need assistance troubleshooting the rough running condition, I recommend having a professional, like one from YourMechanic, inspect the car and move forward with repairs.

How to Identify and Fix Common car Problems ?

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If you see a good spark at the coil, but not at the spark plug, then the problem may be caused by either a bad distributor cap, rotor, or carbon point and/or spring, or plug wires. Look down in the spark plug tube. If you see the spark going to the tube, the boot is bad.
worn spark plugs. worn or bad spark plug wires. worn or bad distributor cap. worn or bad rotor.
A Bad Crankshaft Position Sensor

The crankshaft position sensor monitors the position and rotational speeds of the crankshaft. Without the crank sensor, the engine control module (ECM) wouldn`t know when to fire the fuel injectors and ignite the spark plugs.

A clogged or failed exhaust gas recirculation or crankcase ventilation valve or faulty oxygen sensor can send the wrong signals to the computer and cause misfires.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
The most common causes of misfires are worn, improperly installed, and mishandled spark plugs, malfunctioning ignition coils, carbon tracking, faulty spark plug wires and vacuum leaks.
If your engine is not sparking, it may be due to a problem with the CDI box. However, other potential causes of no spark include issues with the ignition coil, spark plug, or wiring.
If you do not see a spark, there is an ignition problem. Remove a plug wire and insert an old spark plug or a spark plug tester into the end of the wire (the plug boot). Place the spark plug on a metal surface on the engine, or ground the spark plug tester to the engine. Then crank the engine to check for a spark.
The battery, a generator and a more complete vehicle electrical system provided a relatively stable electrical supply to the ignition coil.
On modern auto-start/auto-stop engines, the camshaft position sensor determines which cylinder is in its power stroke relative to the crankshaft position, delivering fuel and spark to start the engine when you step on the accelerator.
The ESC module is one of the components that directly controls engine spark, so if it fails, it can leave the vehicle without spark. A vehicle without spark may still crank, but will not be able to start or run.
your engine misfires and shakes: if a map sensor reports a false high pressure reading, the engine`s computer will signal for more fuel. this results in a rich mixture, which can foul the spark plugs and cause a cylinder not to fire.
Engines that idle in a clunky or rough manner could be suffering from misfiring. In essence, when a misfire occurs and the air to fuel mixture in the cylinder becomes compromised, your engine essentially may jump up and down, causing your car to start and stop suddenly.
Once the engine is cranked, you should look for blue sparks along the spark plug gap. If you can see blue sparks, this proves your ignition coil is working correctly. If you don`t see blue sparks or you see orange sparks, this is a sign that there`s a problem with your ignition coil.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

replaced bad coil pack and new coil not sparking car starts but runs rough engine light on blinks sometimes
ANSWER : Hello and thank you for your questions. If your engine was rebuilt about 10 months ago, the question is to determine if the management system has been installed as well. With the symptoms that you are having, it sounds like the coil packs are old and in need of replace. You replaced numbers 1 and 4 and now number 6 is not firing. I recommend replacing number 6, 2, 3, and 5. This will ensure that you have all 6 coil packs that are new.

Just because the coil packs are okay during a test doesn’t mean that they are functioning correctly. Coil packs on Buick vehicles from 1998 – 2005 last between 150,000 to 200,000 miles. I also recommend having your fuel injection system flushed. Unless you have new injectors, the old injectors could cause a cylinder to fail, even though it is working correctly. These symptoms can cause the engine to have a rough idle and rough running during conditions. If you need assistance troubleshooting the rough running condition, I recommend having a professional, like one from YourMechanic, inspect the car and move forward with repairs.

Car won’t start. The check engine light, battery light, and oil change light are coming on. I tried jumping the car and nothing happened. Why won’t my car start?
ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

engine light-p303 cylinder 3 misfire, changed spark plugs,ingition coil and cylinder valves
ANSWER : Coils and plugs are usually the starting point for a misfire code, but some basic diagnostic work might save you some money. Sometimes I like to try swapping components from cylinder to cylinder to see if the misfire moves before buying expensive parts. There are a few other problems that could lead to a P0303, like ignition primary problems, vacuum leaks, or bad injectors, but those things are usually accompanied by other codes. It’s clear that you have a dead miss. When the ECU sees a consistent misfire, it shuts off the fuel to that cylinder to prevent damage to the catalyst. The the CEL will start blinking to warn you that you may be doing damage by continuing to drive. You’re at a point where you need to have a professional do some diagnostic work. by contacting Your Mechanic, you can have a technician come to your home or office to check out your misfiring VW and recommend a fix.

Engine light fault. There was a bad spark plug and a failed ignition coil. Replaced both the coil pack or spark plug.
ANSWER : Hi there. If the light is coming on then shutting off and returning on, then if the issue is for the same coil, there could be an issue with the wiring on the coil plug. Check the wiring on the coil plug and see if the wires are split, broken, or burned. If there is nothing wrong with the plug, then the main engine harness has an issue / short and may need replaced. If you need further assistance with your ignition system, then seek out a professional, such as one from Your Mechanic, to help you.

My car will not start Intermittently. I purchased a new battery 2 weeks ago and yesterday the car wouldn’t start. Got a jump and
ANSWER : The issue you are having is probably due to an intermittent fault in the starter motor itself or a deficiency in the starter electrical circuit, for example a large voltage drop due to a poor ground or a high resistance connection. These issues can be readily diagnosed and resolved on a mobile basis if you request a hard starting diagnostic. If you request that diagnostic, the responding certified mechanic will get this resolved for you promptly. Based on Toyota’s Factory Service Manual, the battery should not be disconnected if the vehicle engine is running. The battery acts as a large resistive voltage sink and consequently taking the battery out of the circuit, while the alternator is still running, can create a voltage spike on the car’s electrical system which is not good for voltage sensitive components such as the engine computer. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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in my car battery warning light appearing while driving.so I have replaced both battery and alternater still light is on
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have code p0017 dealer is telling me i need a new engine is this because they dont know what to do next to my car .?
ANSWER : As you may have already learned, the code p0017 indicates an issue with the crankshaft position sensor. This would mean that that transmission doesn’t understand the speed and can’t send the same information to the transmission. I don’t think your car needs a new engine just based on this code alone. With all the repairs that you’ve done, it’s possible that the ECM is faulty and is producing the code. I recommend having a professional mechanic, such as one from YourMechanic, reset the codes and inspect the Check Engine Light thoroughly in order to make a proper diagnosis.