Car jerks and misfires?

Car quit running yesterday. Son heard all sorts of knocking, loss of pwr. Turned if off, ckd oil (good) and and called for help. By the time I arrived, car was cool. Stuck in key and it fired right up, ran fine. Follow him home for about 2 miles then problem came back. Engine misfiring. Knocking noise too, but probably from motor mounts. We towed it home. Went out this morning and it fired right up, ran fine. Drove around w/no issues at all. Can't reproduce. Intermittent problem. MIL is not on either.

Thinking a "soft" coil, perhaps even crank/cam sensor issue(s). Any thoughts or troubleshooting tips to share?

The knocking only occurs when the engine is misfiring. I believe that's coming from one of the rear motor mounts (the car has been wrecked in the front before). There is no smoke from the exhaust when this happens.

After a bit of checking, I think this issue came about as 1) some bad gas (water) and 2) perhaps a sticky injector. I treated the fuel with the typical water absorb / fuel injector cleaner. I drove it for over 40 miles today and it hasn't exhibited any misfiring issues at all.

Odd part of all this is that the check engine light never was tripped. I'd think that any type of misfire would have tripped the check engine light, but perhaps that only happens when there is an electrical misfire.

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Saturday, December 26th, 2020 AT 2:04 PM (Merged)

This problem is gradually getting worse. The engine is shuddering at irregular intervals when cold, especially idling or when accelerating. The engine almost stalled today when I was at the lights.

However, when the engine is warm, it runs smoothly. It was serviced only a month ago and spark plugs were replaced. Since the symptoms are very specific, I hope someone smart can narrow down the possibilities.

I used a Acron CP1980 Scranner and got codes P0300 P3001 and P0302 Which
are multiple and misfires in cylinders 1 and 2. The car runs fine untill it warms up then it misfires. The spark plugs were just replaced. It ran fine after they were replaced but this problem started shortly after.
Could this be the Fuel pump located in the tank.

Isn't there a fuel sensor that should give you a ODB II code on your reader if the problem were fuel related. Like low pressure from the fuel pump or injectors malfunctioning. There is a fuel sensor reading on my Acutron 1980. It just sais Fuel Sensor OK. I think the problem is with one of the 1ZZ-FE coils that sit over the spark plugs. Is there a way to test them using a ohm meter. For say one with a colapsing coil.

Thanks for the info on the fuel testing what's the TB.
I think I fixed the problem but don't understand why.
When I purchased the $3 NGK's they said to gap at.44 So I opened them up.10 from there factory setting and installed them and shortly after I had the problems with the car. To repair the car I pulled them and went to.38 gap and the problems almost gone. I bet if I go to the original.35 there will be no problem. Now its great though. I also pulled the springs apart inside the Coil housing so they would make better contact. These plugs being platnum I don't think they should have been gapped at all but the auto parts store said they had to be. I think the.44 would be for standard large electrode plugs.

Engine seems to miss when you go up hills and you pressdown slowly for more fuel as you do all at once it takes off and you have lots of power, some times its ok but 75% of the time not good also hard on fuel when this happens.

Hi, so I've owned this car for close to a year. Always trying to keep up on maintenance to it and fixing problems
2 days ago I had replaced the PCV valve and hose then the next day drove about 50 miles to Riverside and back another 50 home. Today when I was out and about I decided to check my check engine light (I have a code but already know it and the solution) but now I have a random misfire and cylinder 1, 3, and 4 are also misfiring

I checked all plugs and hoses I touch while working on other things that day (suspension stuff) and all are plugged in and attached.

It ran pretty bad this morning (it was colder then normal this morning) the idle was worse then normal and it was shaking a good bit but once it got up to temperature it ran perfect it didn't feel like anything was missing or running oddly.
I would definitely appreciate any aid you guys and or gals can give. Thank you

When I bought it a year ago I asked what all had been replaced recently to know where my tune up and fact checking begin (to see if he actually replaced those items) which he did but the PCV valve wasn't one and I normally do it on any vehicle I buy it's inexpensive and generally simple.
It may be that my computer hasn't registered all the monitors? But I'll definitely check the vacuum tomorrow morning unfortunately I am at work at the moment and unable to do so now, but any other advice you could give is definitely welcomed.
Do you have a preferred way to check for vacuum leaks?

Update you tomorrow, thank you.

I have a 2010 Toyota Corolla with 66,000 miles on it. When accelerating my car, it becomes bumpy between 20-40 miles per hour. I don’t notice this happening while on the highway. I’ve had a couple of mechanics tell me they think it could be either the coil pack, spark plugs or fuel filter. I have 2 questions. First, how can I test the coils and spark plugs to see if they are good or bad and second, do you have any other suggestions on what might be the problem? Thanks for your help!