Greetings, thanks for past help - it's amazing to me how much help I have gotten without ever having to post a question. I am constantly checking the dates to think about how far in the past you have answered questions that I hadn't yet asked. I want to say more but I constantly stray from one sidetrack to sidetracks off of sidetracks..... I got a vibration - maybe even a knock, and didn't get a check engine light right away, I mostly drive short trips 3-4 miles, it occurs after about a mile or so, I drove it about 3 times before I stopped driving it, and read about destroying the catalytic converter by dumping unburned fuel through and back out of the engine, -- I don't think I even got a check engine light until the 3rd time I drove it - (I already had the Autel AP200 plugged in, and got the P0302 - even before the check engine light came on, but once the check engine light came on I don't think I got any additional codes) Perhaps I haven't searched enough to make sure this hasn't been answered before - but a starting point that I read probably even before getting to priuschat was to: change spark plug 2 to some other cylinder, and change the coil from cylinder 2 to some other other cylinder, and see where the misfire lands. I looked at a YouTube video on changing the spark plugs, and saw the coils are different lengths..? I think, is it even possible to swap coils like that assist isolating the trouble? should I just change all 4 spark plugs first, or try and isolate it more 1st ? or something else ? (and is it something I really ought not drive until I get it fixed? ) it has been P0302 ie just cylinder 2 each time I can't believe I have had this car for I think more than 2 years -- in choosing this one over another I spent money on the car fax, and saw the previous owner seemed to have taken it to the dealer for all the recommended scheduled maintenance, I changed the air filter, have changed the oil and filter a time or two, but haven't changed spark plugs - assuming they got changed at 1st recommended interval 100K ? , they maybe have 40k on them -- pure speculation though --- probably unnecessary extra info- though if this spurs unrelated advice to the main question, it will be appreciated: [I had been getting red triangle and P00A6 in my 1st 6 months or so of owning it (I cleared it a time or two and it hasn't come back for a year or more I think due to daily driving it- and perhaps cleaning up some water / humidity); 2-3 weeks back I finally used the MAF cleaner I ordered going on 2 years ago, for the lean running error - p0171- I would get mostly when I went up a hill - (meaning I went across the Mississippi river bridge); I wanted to be able to clear the fuel trim memory afterwards with the autel and couldn't figure out how - but ended up getting a running rich code before I acquiesced and unplugged the battery for a bit to clear the KAM? also recently and I didn't post this one but I wanted to : "hit an alligator. what part is this? " replaced the Coolant Heat Storage Tank - the canister was ok, but the valve and what not underneath it was destroyed -- I never got any error codes from that ordeal- but did add back in just about 2 gallons of new toyota SLL coolant (thanks for help getting that refilled and getting the bubbles out, @Patrick Wong @ChapmanF and others btw ) thanks for any and all advice
The ECM is able to math about the engine load, RPM, and misfire severity, and the likelihood of sending enough unburned fuel downstream to pose risks to the cat. If it detects a misfire, you will see the check-engine light. If it thinks the misfire is bad enough to be a risk to the cat, you will see the check-engine light flashing.
hey, thanks for replying. when I was describing (and replaying in my head in order to type it) the check engine light coming on sequence - it didn't make much sense that I was able to pull an an error code without having seen the check engine light, [ I think it must have been the combination meter issue- that was messing with my recollection -- it only acts up maybe 20% of the time, almost always after a quick stop, when the battery has been getting charged, so I can usually make it work by turning the car on, turning on the interior lights, rolling the windows down, turning on the headlights, ie trying to bring down the 12v battery voltage a little; I'm kind of used to it, so dealing with it is a little unconscious (I ordered one from Matt with Texas Hybrid - also a year or two ago, and since I am sort of mentally deficient when interacting with the movement of time, I don't know when I will find time to install it - though now the mileage he programmed to match is going to be off by 8-10k miles- and I wonder whether he'll want to give me a core charge return)] but anyway I don't think it (the check engine light) was flashing, I think it was just on and steady, when I drove it while the combination meter was working --- but back to my original question, even if I am giving poor / wrong symptom descriptions, can I / should I / would you swap the spark plugs, and or coils or just replace the spark plugs first? or do something else, or collect more data some kind of way for the advice givers?
