Irish25

Ok My trucks started to misfire after I stopped on the way home from work the other day. Truck was running fine as usual stopped at the store and once I restarted it was missing like crazy. Got it home and it showed a P0304 code misfire in #4. Ok I pulled the spark plug and it showed alittle wear . Put it back in after dinner and it started fine ran great all the way to the parts store. But once I got what I needed and restarted the truck it started missing again ? So I cut it off and went back inside to talk to the guy at the counter and see if they had any coils for it. Of course they had to order them. When I went to leave started my truck up and it was running fine. Next morning I said well lets see truck starts right up ...runs fine all the way to work ( 30 miles ) stop for coffee and when I get back in started missing again? So I get it to work and after work starts right up and runs fine? This morning same thing happend once I stopped and restarted it rough idle and missing. My coil should be here today and I plan on changing all the plugs and putting a new coil on #4 . Anyone ever have this happen to them ? Seems to only misfire after I stop and engine is warm . But runs fine if its cold .Do you guys think am heading in the right direction buy changing plugs and that #4 coil ?
2002 tacome 250.000 miles
thanks for any replies

75w90mantraN

Sounds good what you did. I might have swapped out a diff coil pack to rule out a bad coil. But at 250k, its prob time. Hopefully you had it solved.
Take me years to reach 250. Lot of posts of Toys above and beyond. Good feeling everyday.

shaeff

Was this ever actually resolved? My '02 3rzfe is doing exactly this with only 112k on it. I've replaced the plugs, coils 2 and 3, checked for vacuum leaks, etc... I get two codes, random misfire and cylinder 3 misfire. I even swapped coils around to see if the misfire chased the coil and it did not.

When I listen to the injectors, #'s 1,2.and 4 all sound like a click click click, #3 sounds like a thunk thunk thunk. Should I replace the injectors? They're not that expensive and it may be worth a shot.

When I fire it up cold, it runs like a top. I can drive it 300 miles and it'll run perfectly. If I shut it down, let it sit for 5-10 minutes, then restart, I will get a cylinder 3 misfire EVERY time.I keep reading horror stories about cracked heads. I bought this truck after my '94 22re 4x4 finally died at 235k. I really needed a reliable truck. Suggestions, anyone?

75w90mantraN

http://troubleshootmyvehicle.com/toy...el-injectors-1
I had the same codes and symptoms no matter the engine temp, just when accelerating with more throttle. I'll be testing mine.

Link is for a diff engine, but operation is generally the same.

75w90mantraN

http://www.toyota-4runner.org/3rd-ge...A%2A%2A-3.html
Another helpful link....though on diff engine, troubleshooting is generally the same.

I tested resistance on both the suspected injector and a good one and both were in spec. Ran the engine and idling got worse when I dc either injector (#1 and 3).
Looked at coil packs and forgot about the corrosion on pack #1 by the plug wire connection. So likely replacing that. Coil pack #3 was in spec for resistance check. But I kinda doubt it last longer too, bunch of soot in the plug chamber. Plus, the readings wouldn't stay in spec like other measurements. So its prob on its way out too.
Wires, plugs are new. MAF is good and clean.
I do have a slow valve cover gasket leak. Compression checked a couple yrs ago, so it's worth a recheck. But no burning oil.
Fuel pressure check can be another possibility for misfires. For me, I'd do that last, so I don't have input yet.

So its good practice to be methodical. Otherwise parts replacing can be a blind and frustrating experience.

Then again with extended mileages on these beasts, new parts wont hurt and shouldn't disappoint, even if the problem isn't solved completely. Preventative maintenance is never a bad thing.

shaeff

Thanks for the links. Coils on 2 and 3 are new on mine, new plugs as well. No carbon arcs on any of them. When I get a chance, I'll unplug #3 injector and listen to the motor. I'm hoping for either A) no change, or B) very little change.

75w90mantraN

Turns out I had carbon tracking in plug #3. After reading this http://www.underhoodservice.com/spar...ent-dos-donts/
I might as well replace the still 'new' plug.
In my case, the previous owner(s) messed up the sparkplug threads. So a lot of the combustion gasses likely came through (mine looks exactly as the ones pictured in the link) and interfered with the coils, which prob are original. Go figure. Now I'm hoping my 'new' wires might still be re-usable. Its only been a few yrs.
Wonder how cleaning the threads will turn out...otherwise it be replacing plugs every few yrs for that one cylinder.
Good to recheck past work. Be surprised what you find.

75w90mantraN

Update is new ngk coppers and wires, a refurbished Toyota genuine coil pack, and salvaged coil boot were what fixed my misfire codes and symptoms.
Turns out I had 50k on the iridiums and wires (!) But on a waste spark setup, that's not bad. Didn't know then. Now, going back stock feels like an upgrade. I missed the throttle response, especially going uphill.

Time will tell on the refurbished coil. Only $30 to try.

shaeff

Figured I'd update on my problem for others' future reference.

After a compression test, leakdown test, new 2/3 coils, and new plugs, my problem persisted. Passed the compression and leakdown tests just fine.

As I mentioned earlier, injectors 1,2, and 4 all made a click click click while operating. Injector 3 made more of a thunk thunk thunk sound while operating. This should have been my first step, but I hooked up my code reader to confirm that I still had #3 misfire. Confirmed. Next I looked at the o2 sensor data. Primary sensor was reading rich, secondary sensor was reading lean.

Next I pulled up the long term fuel trim (LTFT on the scanner). It showed 27%. I asked my mechanic friend what that meant, he said normal should be around 3%, so that likely points back at a bad injector. It seems that while injector 3 was dribbling fuel, the others were compensating by dumping fuel to try to make up the difference.

Ordered an injector, new grommets and o-rings for the rest, put it all in, truck runs like a top. No more misfiring, no stumbling, runs WAY better in general. I probably should have replaced or rebuilt all the injectors, but it's expensive to replace and I don't have time to wait on a rebuild service.

75w90mantraN

Thought I'd give an update. Apparently this problematic cylinder blew out the plug and gave out a multiple misfire code again a few months ago.

Took the risk of attempting to repair the threads with a Time-sert but unfortunately dropped the tap down the hole.
Took me the better part of May into June tearing it down to the top of the block just to fish it out and then do my best to redo the head surfaces. But last week, the test drive left me stranded on an unsafe narrow stretch of road that had me decide on getting a shop (good one) to help me on what I messed up. Both me and the shop owner were convinced the tear-down on a high mileage engine might not have panned out....
Turns out, compression tests were in fact good and the issue (my fault) was a leaking coolant hose into the firewall and vac leak by the intake manifold. Holding on to a batt that doesn't hold a charge is also a no-brainer but I'll carry a spare and see just how much more I can crank out.
Local shop and tow was there when I needed one. But I said I'd take it from there with the actual repair. Wouldn't mind working for them.

So yeah I tell my buddies if they ever buy used, better have good plug threads! Mine lasted a good 9 yrs before it blew out! This 5vz-fe continues to amaze me...as well as time-sert.