Just throwing this out here but I would have a compression test performed ASAP......All the codes you are explaining can mean any number of things....some easy to fix others Really expensive to fix... Had similiar issues on my 3rzfe motor @ 67k miles and it turned out to be a massive issue of burnt valves partially caused by a really small exhaust leak and something else I cant explain... like i said just throwing out suggestions to look into. Dont wait to long because the longer you wait the worse it gets trust me....

You could try a new fuel filter and maybe a fuel pump. Those are possible causes.

Just replaced the fuel filter a few months ago.

Bought a compression tester tonight, hopefully will work on it tomorrow night.

I am going through the same thing right now
Acouple of months back I had that small shuddering at around 55 (CEL read 3 cyl mis) new plugs wires and a coil pack fixed it
This morning I fired it up and got a real bad misfire and shaking CEL flashing I stopped and got the CEL read and it was #2 misfire ok I said I'll replace that coil pack and that should fix it ....... no dice pulled the plug it fired it up and it sparks
I am at a loss so off to my mechanic I go i hope it is not terminal only 245k on the clock

Don't know that a spark @ low RPM will get you the consistent spark you need at 55mph. I would still suspect the coil is not keeping up. You can swap the coils around and see if the misfire follows the coil.

i've swapped coils, so I know its not them. I am going to try, weather permitting, to lurk around the engine and look over things. I find that if I just start it and drive, no problems at all.

bob

UPDATE:
On my way to work this morning, got about 5 miles away from work and its started again...rough idle, exhaust sounded like I didn't have one, between 50 and 60mph the 4Runner shook...but the CEL never came on. Pulled into work look over the engine real quick...pulled the spark plug boot off cyl #2...could hear the wire firing...stil never thru a code. I going to do the compression test tonight.

So after looking up the paperwork on my 4Runner, i found out I still have a 1yr warranty on my Jasper Engine the previous owner installed. Took it to the installer and had him look it over. He said it was the coil pack and it needed to be replaced.

So $95 later, pack installed............running smoother but still thowing P0302. Guess it's time to take it to Toyota and let them deal with it.

Quick question though, If I was in a minor front end accident where I rear ended a Saturn, my right front corner struck the left rear corner of the car, would that of caused anything?

Bob

Hello BobLMTDT4R,

I know it's been a while since this issue had happened to you, but what was the final outcome? Did you ever find out why your truck was reading code P302? Did you ever take it to the dealer?

I'm going thru a very similar situation and I believe that ultimately my solution will be in the Fuel Delivery system. Any advice you can provide from your experience will be helpful.

VR,
P

Wow.

It's so funny how long it's been since my one and only ONE post here on t4r.org. To sum up the difference from then to now:

Bob and I PM-ed a couple of time and I ended up getting a stethoscope to listen for the difference in injector noises. It turned out it was definitely my injectors. I got them rebuilt and my T4R has been running great since. The only thing it needs done right now is minor routine maintenance.

Thanks again Bob.

VR,
P

Thanks for the update, most threads never say what the final root cause was, it's the most important part.

This sounds similar to my truck. I get P0300, P0301 and P0304 and stall from time-to-time as well, with a quick restart (fun coming off the highway!). I've done the coil pack test and have driven it since August when it started. I was in Northern Nevada at the time. To me, it seems like you and I are suffering from some old injectors or coil packs. I've also done new plugs and wires. I actually need to re-do my valve cover gaskets since mine are getting some oil in the 4th cylinder. I suppose I'll do the injector when I do that. I'm a broke student, so right now I'm just hoppin' and poppin' instead of skeetin' and yeetin'. It isn't the end of days, but it is something you and I should fix sooner rather than later before we get hit with the dreaded *shudder* compression.

Sorry to ask on this thread - I cannot seem to start a new post yet -

99 4runner - 201K
I got a P0305 code. I went ahead and changed all the plugs, coil packs and injectors. It ran great for about a week but now is running rough again and just threw P0305 and P0302 codes. -

What else could it be?

Have you done a compression test? Did you change the spark plug wires as well? What brand parts did you use for coil packs/injectors/spark plugs?

Cylinders 2 and 5 share the same coil pack. Swap the coil packs on cylinders 5 and 3 and see if the misfire follows it. Also check spark plug wire routing.

Attached Files

3rd Gen T4R 3.4L Spark Plug Wire Routing.doc (82.0 KB, 12 views)