My 03 Chev Avalanche is giving me a P0300 code (multiple or random misfire). With no distributor or individual coil is this something I can fix myself or is it shop time?
View 6 RepliesI have a 2000 Impala with a 3800 V6 series 2 with 165,000 miles. The only code I had was a P0300 Multiple random misfire that occured off and on at first, Worse in the city Better on Highway. It would start running on half the cylinders and bogged down, with the check engine light flashing, after getting onto the highway it would straighten itself out at first. I thought i had water in the gas so i ran some heat through it. straightened out for a day then happened again so I thought maybe a should run some premium gas in it, The car ran like total crap until the premium was gone, so i thought maybe it's running too rich, I put 87octane in it and it ran great for a day or two, then it gradually got worse to where it would not straighten up on the highway, tried to die at stoplights and i had to drive it with 2 feet to get it home and park it. I've replaced the battery, spark plugs, wires, ICM checked good, coil packs are good, replaced fuel Pressure regulator, looked for arcing on the spark plug heat shields and it will not start. It turns over but doesn't try to ignite and when I get the slightest rumble of ignition, it backfires up through the manifold and I see a puff of gas or light smoke by the exhaust manifold.
The car had a vacuum leak around the intake manifold cover gasket and a leak on the fuel rail. I pulled the fuel rail off my impala, snugged up the rest of the intake bolts then disassembled the fuel rail, flushed it out and cleaned the injectors the best i could, then reassembled it. before i re-installed the fuel rail I hooked it up to the fuel lines outside of the engine and tried to start the vehicle. all injectors had a nice spray pattern. So i installed the rail and it still didn't start but it had more combustion than before although it's still backfiring like before. Checked the fuel pressure by turning the key on and the fuel pressure went to zero very fast. I blew the rail out with air so to make sure i didn't damage the regulator I replaced it with the old one, ran the test again with same results, so i reinstalled the new regulator. I performed the fuel pressure test a few more times while moving the fuel hoses and when i moved the back supply line the vacuum loss stopped then dropped to zero when i let off of it. So I replaced the fuel line connector and O-rings on the injectors. It no longer has a vacuum leak.
I cleaned the EGR Valve out and had no luck there, then I removed the Idle Air Control Valve-pushed the pintle in, re-ionstalled it and WooHoo! it started! Although it still ran like crap with the same random misfire I was still happy to hear it start.I pulled the plugs on it to do a compression test and all 6 cylinders have between 180-190psi so the engine is in good condition mechanically. I installed new plugs before getting the car restarted and when i removed them for the test they were covered in thick black soot after running for roughly 15 minutes max.
I have (2) 2000 Chevy Impala's so I've swapped sensors from my wifes car to see if it would fix it. I've tested the following MAP, MAF, IAC, coil packs and ECM. None of these made the car change. I believe it is a timing chain because the car has never had a new timing chain and is way overdue, but I haven't had a code for a crankshaft position sensor. Can the timing chain be bad without throwing a code? It's not out of time enough to change the valve timing because I had a good compression test but its not firing right and still has the multiple random misfire. I have not checked or received a trouble code for o2 sensors, crankshaft position sensor or cam sensor. Something has the timing retarded and is dumping extra fuel into the engine because my new plugs looked like they were in the engine for a year.
I have a 2007 Hyundai Accent GLS. I just got it from a used car dealership (local) and it runs perfectly. It had a misfire code when i first got it, for all cylinders plus the p0300. It went away when i started the engine again, and didnt come back til a month later (Now). now it wont go away.
I went to advance auto and had them use their OBD2 reader for a trouble code and i got p0300, p0301, p0303, p0304. No other codes present.
I am not feeling anything bad, and from what I am told, a misfire feels like a hard shift. This is of course after getting the plugs and wires changes as well as an oil change. Standard preventative maintenance.
The mechanic used OEM parts got from local parts shop. i think the OEM plugs are the copper ones. I would have preferred iridium as they arent that much more expensive but I don't want to pay for another plug change.
The only symptoms I can think of, is that according to google, I should get around 380 miles to a full tank (11.9 capacity, 32 mpg city). I am only getting 280 from full tank to gas light.
I have also gone through a lot of oil. I checked the dipstick and it was below the low line, so i bought a quart of high mileage oil (same exact brand and type of oil that i gave to the mechanic to use) and it went to just above the full line. This was at around 1500 miles after oil change.
After visiting multiple sites about misfires, i found a few things that caught my attention. One is a site called auto service professional, which talks about the OCV for the MC accent. A lot of sites also recommend gaping the plugs at .035.
Just started getting a p0300 random misfire code on the durango a couple days ago. pretty sure it isn't moisture related since it started on a nice sunny day. it was running pretty rough so it was obvious that it was misfiring. I changed the plugs since it was about time anyway, and they needed it and I cleared the codes. new plugs (put in the oem champion copper plugs) didn't make the problem go away. The engine still ran rough and the code came back. 2 of the plugs looked like they may have been fouling a little bit. they were a fair bit blacker than the rest of the plugs. I went ahead and changed the coils on those two cylinders and reset the codes again. Still runs rough and the p0300 came back. where do I go from here? I am not getting any specific cylinder codes so it makes sense to me that it isn't one or two cylinders not getting spark. 2003 durango 4.7 ....
View 6 Replies'02 TB w/ code P0300 / Random misfire. Started the other day when it was very damp out, FWIW. Feels like ur driving on rumble strips during acceleration. Rough idle also. It does not do this continually though as after a while (minute) it clears up and runs smooth for a while then runs rough & light will again for a while. I seafoamed it today since it been about 60k since last seafoam. I thought that might have worked until I drove about 20 mile and it went rough again. I also cleaned the oil out of the cam sensor elect connector, since that caused rough running before, although it didn't throw that code. It seems to be very intermittent. '02 TB, 185k miles, orig plugs changed at 125k. Is it actually just going in & out of a limp-mode? O2 since it's random ???
View 14 RepliesRecently i started the car and it was shaking more that usual. the CEL light came stating P0300 with random misfires. It sounds and feels like misfires so i believe this is true.
View 10 Replies2004 GMC Sierra 2500 HD, 227,000 miles 6.0L V8.
While driving up hills or increasing load, the CEL will flash multiple times, I pull over as I know CEL flashing is not good. I turn the truck off, allow it to sit for a few minutes, whip out the code scanner, only code that was there happens to be P0300. Truck has poor MPGS, idles rough, loss of power. this happens every time I drive this vehicle as I use this truck to pull my trailer that weighs around 4000 lbs. Problems come and go. Some days I can drive the truck for an hour with no problems, come up to a red-light, BAM, CEL is flashing, truck is bouncing side to side due to the poor idle, other days this happens while sitting in the parking lot of my job with the ac on.
Truck has been to the shop several times as I'm no mechanic. Parts replaced are as follows:
- Fuel pump
- Throttle Body
- All plugs
- All wires-All Coils
- Intake Manifold Gasket-
- Battery
- Sensor 1 Bank 1 O2 Sensor
- Sensor 1 Bank 2 O2 sensor
I have a 2004 Hyundai Santa Fe 3.5L V6 when i was driving a couple of days ago the check engine light flashed and after a while it stayed on the codes are P0300 which is a random misfire as well as a misfire in cylinder 2, 4 and 6
I replaced all 6 spark plugs and the 3 spark plug wires still the same issue. The car hesitates when accelerating when i accelerate it looks like it wants to stop the rpm goes to almost zero and then it moves and so on. the rpm goes up and down like crazy.
Sometimes it won't move past 1000 rpm I'm moving 60mph and still on 1000rpm and sometimes it works just fine like there is no issue at all. When idle the car is fine and everything seems normal it stays on 900rpm. The car has 158K miles on it.
I uploaded a video to show you what's happening to the tachometer when I accelerate [URL] ....
I'm on a limited budget I'm thinking of changing the ignition coils but i want to make sure that's what is causing the problem first because i spent 200$ to change spark plugs and wires and the mechanic didn't fix the issue.
Had this code show up after the warning light came on and then the light went away after two day, the car seems to be a little sluggish now. I have read that this is a random engine misfire and it could be a bad plug..
View 1 RepliesI know it is a random cylinder misfire code however I started my car in the morning and it was fine I moved it and put it back in my driveway. I started it up later and waited for it to heat up i came back outside 10 min later and my check engine light was flashing and my car was shaking like crazy you could tell the engine was misfiring like crazy. I had under a quarter of a tank but not empty yet. I shut it off and turned it back on and it was still doing it. I drove the mile to the gas station the way it was.
Under partial throttle it was revving to 4500 and over 5, had to let of throttle to make the car shift up a gear. I filled up and started the car again performed fine after that however the check engine light was solid now and still on. I went to my local mechanic and he read that code P0300. I changed my spark plugs that day and they were crap the original spark plugs I have 65,xxx on my car now. Car is smooth now. I cleared check engine when i saw him first and it did not come back on all day even before i changed the spark plugs later that night. Why my light was flashing and why my car was acting like that till i filled up?
I purchased a 2010 camry 4cyl. and i have this code of random multiple misfire, along with misfire on all 4 cyl. plus the P2716 code.
I had some issues with the fuel pump, got stuck, replaced it with a after market one, car did not run at all with it. So i decided to test the original one one more time. It worked, so i installed it back. The car starts just fine, takes off smooth, but when i get to 35-40 mph, the check engine light will blink, if i press the gas the engine will shake a little bit, and i can feel there is no power at the engine.
If i release the pedal for a moment and than press it again will run fine until i reach 35-40 mph. If it's in park, i pus the rpm up to 7k, engine runs just fine, no blinking check engine light, no engine shaking....
Like i said, 6 codes, 4 for each cylinder misfire, 1 for random multiple misfire, and p2716 solenoid....
New plug on right, lower bank 2 plug on left
Started getting a P0300 and various misfire codes for random cylinders. Truck has 95,000 kilometers so figured I would change the plugs. Several of the plugs on the lower bank on both sides were pretty much toast. Most of the plugs on the top looked good. All of the plugs had a small deposit where the spark hits the ground probe. Picture is typical plug from lower side. changing the plugs should make a big difference in how she runs and eliminate the codes.
Took right on 4 hours same as dealer said it would. I would have got it quicker but it was not a race.
I was driving along and the engine started missing really bad. The whole car was bouncing around. At first I thought I had a flat, but when I stopped I noticed it was the engine. I checked the error codes and got 16684 and 16686 --- Random/Multiple Cylinder Misfire.
I had a problem recently with the vacuum hose broken and was causing an error code. Replace the hoses and it has been fine. Checked to make sure that the hoses were secure and they are fine. Doesn't seem to me to be related. So many problems for a car with 57,500 miles
I own a 2002 SC430 with 20,200 miles on it which I purchased new. The other day the check engine light came on. I checked it with the code reader and got the following 2 codes. P0300 (random multiple misfired detected) and C1201 (engine control system malfunction). The car ran great before, now running real ruff and when you drive it has less power.
View 9 RepliesI hookup an OBD2 tester on my Prius 2014 Plugin and saw the OBD2 P0300 - Random Misfire. I did a reset and the error still came on. I also tested my friend Prius 2014 Plugin which is factory stock and had the same error. Wonder if that is by design or not. Going to take my ride into the dealer on Friday for my 25K maintenance and have them look into that error. P0300 can be anything. Hopefully doesn't cause more problems down the run..
View 3 RepliesOK - so is my engine computer toast? The other day on the highway on the way home from work, my check engine light started to flash, and the car on cruise decelerated from 80MPH (ok I was speeding) to 70, and flooring it didn't make is speed up, and that's when i noticed it was shaking a little, so i pull off the highway and it's as if a spark plug was pulled.
So I made it to a parts store to have the code read, then started it back up, all was well. As if nothing ever happened. So I dismissed it as a pocket of water in the fuel or some other oddity.
2 days ago it happened again on the highway. So I pulled into the shoulder, shut off the car, and started it again. Runs fine. Engine computer?
My 07 3.3 SF is throwing P0154 and P0300 codes. Autozone said the P0154 is Bank 2 pre-cat O2 sensor. But exactly which one? The P0300 is random misfire. Could they be related?
View 7 RepliesI am trying to get a 2009 Sonata NF with a 3.3L V6 to run correctly and i have tried everything that i can find and still get the problem. The car runs very rich with a strong gas smell. The engine runs rough but doesn't stall. The car has has period where it runs fine and then the issue returns but is in more frequent and steady now. The car will run for the first 5 minutes great if it is cold and it also runs good at full throttle and the check engine light went off during hard acceleration which seems consistent with getting too much fuel. I bought a BlueDriver to read the codes and I love the data it provides but I am learning all the features.
For a little history the car has 95,250 miles. At 81157 miles the check engine light came on and an independent shop replaced the downstream O2 sensor and the light has been off for 2 years until coming back on recently. The code showing was a P0300. The shop replaced spark plugs and the manifold gasket with and oil change for $775. The check engine light stayed off for about a month and 550 miles. The car was taken back to the shop and they replaced the rear O2 sensor for $429 . The check engine light was off for a couple of days and then returned with the P0300. It might go a couple of days without a problem and then it would return.
This is when I got the car and started reading all the forums i could for possible causes. I saw the Tech Bulletin on the Variable Valve Timing Oil Control Solenoids so i replaced both valves. The check engine light returned with a P0303 for cylinder 3 misfire so i figured it was a coil so i replaced all the coils. The P0300 code returned. I check fuel pressure after seeing a post about fuel pressure regulators causing the problem but the pressure was correct. I changed the Mass Flow Sensor figuring it was getting too much gas but no improvement. I bought the BlueDriver so I could see more than just the codes. The O2 sensor looked erratic so i changed the front upper O2 sensor.
I found the Tech Bulletin about the O2 sensors fuel trim readings and realized there was an upper sensor on the back manifold and it was reading -18% so i changed it and now I don't know which way to go. I currently have the P0303 code confirmed and P0300 pending. With the live data the items that looked strange at idle were O2 Sensor Bank 1 Sensor 2 steady at 99.2% and Calculated Engine Load a 21.6%. The freeze frame data from when the light came on has all the short fuel trim at 0.0% and long term at -0.8% for both banks. Calculated Engine Load was 45.9% even though I was trying to drive slowly at 29 mph. Mass Air was 21.71 g/s, I had been running 3 minutes from a slightly warm start, Absolute engine load was 44.3%. Anything else to check or data I should look at?
Here's the deal with this car i just did head gasket, valve job, all new intake gaskets and spark plugs. Car idles fine and mid throttles fine but with high throttle it wont shift and flashes the random misfire light p0300 it seems to run out of power. I've heard everything from maf sensors to ignition coils and wires. i was just wonder a good place to start and good test to do. I have most testing equipment including scan tool so i can ride with it. o and all cylinders compression tested above 150.....
View 13 RepliesHad the CEL come on twice in the last few days. The first time, a restart of the car took it away. The second time, it came on and stayed over multiple start ups.
With Torque Pro and a bluetooth OBDII dongle I read: P0300 - Powertrain, Random/Multiple Cylinder Misfire Detected
From the Internet:
Possible causes
- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure
I wish it wasn't so broad... But, as the car is about to hit 60,000 miles, I plan to replace the spark plugs (NGK), engine air filter, cabin air filter. Just had the timing belt done last week. I will check all of the intake couplings for tightness.
For others who use Torque, what other settings could be useful in pinning down this issue for me? I cleared the CEL this morning; it didn't come back yet.
Replaced my water pump March 2nd using the "From Below" method. Started the car after and the check engine light was on and water pump was no longer leaking. I drove the GTI to Advance (15 Mins away) it drove fine and I pulled two codes.
P0300 - Random Multiple/Cylinder Misfire
P0301 - Cylinder 1 Misfire
The car pulled and drove normally. The next day the car is misfiring badly. Hesitation and bucks when accelerating until roughly 3k then smooths out.
I will swap my coilpacks and check if the misfire moves as soon as I can get my hands on an OBD2 Scan Tool.
From what I understand about the VR6 :
-The water pump runs off the serpentine belt
-Camshaft timing is controlled by the timing chain.
-Timing chain is not affected by the serpentine belt/pulleys.
Questions :
-Can turning the Crankshaft Pulley affect timing?
-Can that be the cause of the misfire?
24V VR6