P0300 Buick Code - Engine Misfire Detected

My 2000 buick lesabre custom started to sputter and not running properly. It is reading 2 different codes. P0300 which is random misfire as well as P0410 which is secondary air injection system. What would be a smart first move? Any advice would help

Start by checking for intake leaks. Loose or broken hoses around the engine.

my 2002 buick century custom is misfiring and smells like exhaust/gas fumes. reads code p0300 which is randoim misfire, changed plugs/wires, checked coils don't see cracks no leaks anywhere on engine but problem still not fixed...any advice would help

Unfortunately there are many things that could cause the P0300 code. The next step is to replace the air and fuel filter. If the problem persist, the next step is to check the Mass Air Flow (MAF) sensor and catalytic converter.

now if the coil wasn't working would you visibly see damage or could the coil be damaged without visibility? is it possible an injector is clogged and if so adding injector cleaner may help?

Sometimes the coil damage are visible, but usually not.

Yes, fuel injector cleaner can definitely help, if you read the bulletin listed on the "Tech notes" above, the factory recommend using fuel injector cleaner for similar problems.

awesome thanks for the help ill try these tips out, also is there any amount of miles or years that you should change fuel filter?

Actually there is no information in the service manual on how often you have to replace the filter, but I recommend replacing the filter every 30K miles or at least 60K miles.

Lasabre2004 no spark 1/ 4 coil one i chance the coil still thesame no spark but the 2and3 coil have it.it could be IMC is the problem

My 2012 Buick Verano received this code, it also rocks back and forth when at a complete stop????

Unfortunately there are many things that could cause this problem, from bad gas to bad ignition coils. Are there any more codes?

I have a 2008 Buick Lucerne CXL with a 3.8 V6. It has the P0300 code and I believe P0742 Torque Converter Clutch Circuit Stuck On. I have changed the plugs and wires which has helped the misfires. It was not throwing the P0742 code before the plugs and wires were changed. Any ideas?

The codes are not related at all. For the P0742 code you could start by checking the transmission fluid level and condition.

P0742 BUICK - Torque Converter Clutch Circuit Stuck On

Read more: http://www.autocodes.com/p0...

I have a Buick n the p0300 code is showing up I have change spark plugs new wires fuel filter and a crank sensor and a clean the mass flow thing.... I still have problems cranking it up.... Any suggestions

Try adding a fuel additive and use high octane gas, you may have clogged fuel injectors

I have a 2000 Buick lesabre the code po300 showed up I got the spark plugs and wires change and the car still hesitate when it comes to a stop now the car won't start any suggestions?

I am having this issue right now. But mine still starts.... If by chance you got your car fixed can you PLEASE tell me what you did!

I was having the same issue my 2000 buick lesabre was starting every time and it decent at idle but as soon as I put it in reverse or drive you could actually feel the misfires. I replaced the plugs and plug wires. And still was happening. Replaced all three cool packs like an idiot and still was happening. I finally got a new Icm which ran me $138 easy to install and it fixed it right away. I hope this helps

I have a 2001 Buick Century and I just replaced cylinder heads. One of the rockers wasn't tight and backed out and it backfired through the intake. I fixed the rocker, but I'm throwing P0300 and the car won't idle on its own. Any suggestions ?

My 2012 Buick Regal Turbo received this code, it rocks back and forth when at a complete stop. Ive changed the O2 sensor and spark plugs, any advice?

There are some test that needs to be done to determine exactly what the problem is, but according to national database base of repairs for your vehicle, the most likely cause for the P0300 code on your model year is the fuel filter.

is the fuel filter in tank or outside

Inside the fuel tank.

I had the service engine light on I had the light shut off and it keeps turning back on after a few days. When I went and took the emission test and the code comes out as PO300 or PO442

1998 Buick Regal

The P0442 code could be as simple as a loose or damage gas cap.

P0442 BUICK - Evaporative Emission Control System Leak Detected Small Leak
Read more: https://www.autocodes.com/p...

Unfortunately there are many things that can trigger the P0300 code (Items list above), but you could start by replacing the spark plugs and if possible use high octane gas for a couple of weeks.

I have a 2002 Buick Park Avenue. Service engine soon light on and flashing when accelerating. Throwing a P0300 code. We have changed plugs and wires, 2 of 3 coils (the 3rd is good), and added fuel treatment to clean injectors and nothing helps. We did fine a lose wire (had the writing PED 40 on it) that looks like it came lose from someone on the drivers side somewhere in the middle, but begins towards the back of the car. Checked hoses and they all look good with no cracks. Please help! Been going on for a couple weeks and cant figure it out!
Also, if it helps, it started suddenly without warning. It idles rough, faint smell of gas from exhaust, and occassionally stalls when put in gear and also slow to accelerate.

There are many things that can set the P0300 and it looks like that you may have already done all the most common ones.
There a factory service bulletin that includes your model year, the factory suggest that one of the possible causes that can set the P0300 code, is carbon built up on top of the valves. The factory recommends using a top engine cleaner tool and additive at the dealer.
I had similar problem with another vehicle, and since I didn't had the tool from the factory, this worked for me: add a fuel additive bottle and high octane gas, then drive you vehicle for at least 30 minutes at around 3000 RPM, the high RPM will heat up the engine and will soften the carbon on top of the valves, and the fuel additive will clean the carbon. You may have to do that a couple times.

My husband was checking the hoses for cracks and found a wire that was just hanging that looked like it had came lose from something but not sure where it goes or if it could be the cause? It has the writing PED 40 on it.

Do you have a picture? Unfortunately I have no idea what that wire is for.

Right now I dont but can take one and post it.

The wire comes from behind the windshield washer reservoir

My car is showing this code for my 2000 Buick park avenue idk what to do

Unfortunately, then are many thing that can set the P0300 code. You could start by using high octane gas and changing the spark plugs.

My 2005 gm 3800 engine is throwing the P0300 code only, symptoms are rough start and rough idle, I don't seem to have a bad miss at operating speeds. I have replaced ICM and Crank Sensor. I have spark at every coil and my MAF reads 5 g/s at idle and reacts appropriately to throttle. I have changed oil and did run a few treatments through the fuel (seafoam and HEET) but haven't had any luck. I'm thinking I should pull the plugs and visually inspect... Where should I go from here?

Unfortunately, there are many things that could set this code. Let me check if I can find more specific information about your vehicle. What model and year is your vehicle?

It's a 2005 Buick Lesabre.

On that vehicle, the most frequent problem is the ICM, sometimes the spark plugs, ignition coils or the crankshaft position sensor, but most of the time it is the ICM.
Since you have already replaced all those components, I checked a national database of repairs for similar situations and same vehicle, and I found a couple of cases where the new crankshaft position sensors were defective and a couple more where the problem was the fuel pump. I hope that helps. I suggest you next step is to check the fuel pressure when the engine is cold.