Engine misfire?

Its a random misfire code. It means you could have more than 1 cylinder that isn't firing. This can damage your catalytic converters, and give you horrible gas millage and performance. I don't know why the mechanic said to not worry about it. Conman causes could be an ignition problem, spark plugs, spark plug wires, multiple things that would cause this. How is it running, as far as acceleration/performance?

This guide will help us

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Sean

I'm sorry-the car runs great and very smooth, acceleration is great as well as overall performance-no hesitation or kick, and starts right up-that's why he said "don't worry about it now, (maybe to save her money) but if any sign of performance problems, running, or hard starting bring it in. I do plan to diagnose the issue soon starting this weekend, it looks as if I have to go over it very thoroughly. I heard injectors are a big problem on this Toyota model.

If you don't notice any performance issues, then it should be fine to drive until you start to diagnosis the problem. It could be the injectors but it also could be 100 other things. Let me know when you start to diagnosis it and we should be able to figure it out.

Sean

It sounds and feels like it's misfiring on one cylinder at idle speed and up through about 3.5 RPMs. At higher RPMs the problem is undetectable. But the whole car shudders with hesitation during acceleration until higher speeds are reached.

I've changed all of the spark plugs (got fancy new iridium ones), and that didn't help the problem. But I noticed that the ignition coil tubes were covered in oil and the spark plug heads were in oil. So I changed the valve-cover gasket, but that didn't fix the problem. Also, one of the coil tubes is slightly cracked at top part that holds on a rubber gasket.

I tried to isolate the problem, but whenever I disconnected a spark plug wire the engine would just die. So it seems to be an intermittent misfire.

There is no real fuel filter on this car, the whole fuel pump assembly has to be changed, although there is a little strainer that can be replaced. I haven't tried toying with that yet. I don't think it's the fuel pump, but I have no idea.

The air filter is clean. The radiator fluid is good. Transmission is fine. Pieces of plastic are breaking all over the place, and the ceiling foam is falling apart, but otherwise it's been a great car. I can't figure out this problem.

I think that is everything.

Any suggestions?

Thank you for this post I had the same problem and # 3 cylinder has down to 90 pounds it had a burnt valve cost me $980.00 of a valve job runs great!

I recently did a lot of work to it, I changed the exhaust catalytic converter and, all new coil packs, spark plus, fuel injectors, valve cover gasket, mass air flow sensor. I got on a freeway and code p0420 came up and then I got on freeway again to come home and when I got off freeway car was running really rough and codes came up p0300 and p0303. I changed the exhaust and catalytic converter because it was defective. I changed the O2 sensors, and changed spark plugs also gasped them too.044. I swapped #3 coil pack with #1 coil and everything was okay. I recently got on freeway again and when I got of the rough idle was back and so was the two codes p0300 and p0303, when I am around town the car is fine, but when I get on freeway and car is at a high rev it does this.
Your help is greatly appreciated thank you very much.

I took the connection off of every fuel injector and there was a change in engine every time.

I first would like to say this website has been very helpful-I ran the freeze frame data on my scanner and realized the coolant temp did not change-after the car was fully warmed up and upon a complete overnight cold start-which I think indicates a non-functioning coolant temp sensor. I have one on order, however the CEL is on, and could this be a strong possibility that the misfire is caused by this?

Thanks for all your help with diagnosis/answers

My mistake that was from another diagnosis of a different car not related to this question asked, can a coolant sensor cause a CEL to com on and indicate that it is a random misfire?

Thanks

I was decently low on oil, getting close to dot on bottom but wasn't there yet. Could the low oil cause the misfire or is spark, compression or fuel to blame? I've had zero issues before this. Car's at 160,000 miles. Checked using OBD 2 scanner.

Hey Alex, thanks for the response. So, i'm guessing the car being low on oil couldn't have played a factor in the cylinder misfiring. I don't know much about engines I just like to work on my own cars. Is there any way having low oil caused the cylinder to "seize"? Just want to make sure its worth trying sparks, coils and etc. The oil might have been lower then I mentioned because the car was parked on a slope.

Cheers, Kake

Hey Alex, changed the spark plug. Problem still persists. Check Engine light went off. I ran the car for a few seconds. Car vibrates and exhaust sounds like it cuts off like before. The shop I got plugs from didn't have coils otherwise I would have done those too. Should I try coils or fuel injector cleaner next.

Appreciate the help.