Headed home after work and the 2000 4runner started idling rough. Took off at the stop light with very little power and the truck was shaking pretty bad. Check engine light started flashing so I pulled into AutoZone. P0300, p0302, p0304. Also a very rich smell from the exhaust. 2000 4runner, v6 4x4 with 202k
Misfire help!
- Thread starter ASUMTNEER
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mtbtim
Elite Member
This means you are having misfires in the #2, and #4 cylinders which are both on the driver side of the motor and sit next to each other. I'm wondering if your head cracked between the two cylinders and your losing compression as a result. I'd start by pulling all the sparks plugs and doing a compression test of al the cylinders. The video below will help you understand the process. It could be spark plug wires or bad coil packs but these misfires would involve more than one coil pack and the chance two coil packs decided to fail at the same time seems kind of rare to me. If it were actually bad coil packs, the coil pack on the #3 cylinder would be your only good one left. You could swap the position of the #3 coil pack with one of the others and see if the misfire changes and now gives you a cylinder #6 misfire.
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mtbtim
Elite Member
Another thing I just thought of is the weather is starting to get colder and rodents will seek out warm areas to make a nest. Check your engine compartment carefully for any signs of rodents making a home. They have been known to chew up wires and wreak havoc with automobile electronics.
mtbtim
Elite Member
What Spartacus stated is exactly what I would do.
Very possible bad plug coil wire. My one rig had the original spark plugs in it at 215K. It was misfiring because the electrode in the plug broke..
But two breaking at the same time? What are the chances? Maybe the OP should buy some lottery tickets as well.
brillo_76
Elite Member
Mine was very interesting. The po thought he was loosing a rod. As the piece of one electrode stuck in the piston. I saw it with an inspection camera. After I bought the rig with 215k on it. Engine now has 267k on it now. Still perrs like a kitten.
Best to change your plugs by the mfg time interval. So that dosent happen.
Sent from my SM-J337V using Tapatalk
Best to change your plugs by the mfg time interval. So that dosent happen.
Sent from my SM-J337V using Tapatalk
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brillo_76
Elite Member
I only lost 1 plug. It was misfiring and my cel was flashing.
I kept the plug as a conversation piece. 
I will post pictures of it on my build thread. Sent from my SM-J337V using Tapatalk
LittleCaesar
New member
After letting it run, shut it off, and wait for about ten minutes, then see if you smell gas coming from under the hood. If not, then ohm out each injector. I would say possibly a coil in an injector failed.
As other have said though, start with the easy: wires, plugs, coils.
As other have said though, start with the easy: wires, plugs, coils.
mtbtim
Elite Member
Those are your upper and lower intake plenums. The intake manifold is much harder to see. Even if the gasket was bad, that wouldn't cause a misfire.
LittleCaesar
New member
Also, when it is misfiring, grab a long screwdriver and listen to both injectors for the misfiring cylinders.
mtbtim
Elite Member
My suggestion is to do some diagnosing first before throwing money at it. You're having a double misfire on neighboring cylinders. There's been countless people who have started out their search for an answer by changing out perfectly good spark plug wires and coils just to find out the culprit was something else entirely. I've been guilty of throwing parts at problems myself.
Reset the CEL, swap the position of the one know good coil pack on cylinder #3 with either the coil pack on cylinder #1 or cylinder #5 and see if the misfires change. If nothing changes, it's not the coil packs. The wires will be harder to swap because they are different lengths. If you have a friend that also owns a 3rd Gen, maybe you could borrow a couple of his wires to eliminate the possibility of a double spark plug wire failure. Like I said earlier, I find this highly unlikely that 2 wires would fail at the same exact moment.
Reset the CEL, swap the position of the one know good coil pack on cylinder #3 with either the coil pack on cylinder #1 or cylinder #5 and see if the misfires change. If nothing changes, it's not the coil packs. The wires will be harder to swap because they are different lengths. If you have a friend that also owns a 3rd Gen, maybe you could borrow a couple of his wires to eliminate the possibility of a double spark plug wire failure. Like I said earlier, I find this highly unlikely that 2 wires would fail at the same exact moment.
spartacus
Senior Member
If the intake manifold is leaking it can introduce unmetered air into the engine which can throw off the air fuel mixture and cause a lean condition causing a misfire. check for vacuum leaks and also clean the maf sensor.
Don't have time to do anything with it today, but I did stop by AutoZone this morning, where the car still sits, to get my parking pass and decided to erase the codes and start the car. When I scanned for codes, there was nothing there. I started the car and it fired up fine and idled smoothly for the 15 seconds I let it run. I had to get to work, so I couldn't do anything else with it. I'm going to attempt to drive it home this evening and tear into it tomorrow. Thanks for all of the help so far.
LittleCaesar
New member
Could it be a clogged up cat??? I tried to drive it home, but going up a hill shortly out of the parking lot is started struggling hard, cel flashing, and backfiring in the engine bay. My wife was following behind and said it wasn't smoking from the tailpipe. I looked under the hood and there was a bit of smoke, faint, coming from behind the engine near the firewall.
spartacus
Senior Member
brillo_76
Elite Member
Could be a plugged fuel filter. Could be alot of things.
[ spark plugs, wiring, coils, fuel filter, fuel line Plugged fuel filter screen on fuel, bad fuel pump, injectors]
Your going to have to do some troubleshooting to eliminate the possibilities. :]
Sent from my SM-J337V using Tapatalk
[ spark plugs, wiring, coils, fuel filter, fuel line Plugged fuel filter screen on fuel, bad fuel pump, injectors]
Your going to have to do some troubleshooting to eliminate the possibilities. :]
Sent from my SM-J337V using Tapatalk
This is the correct answer. I suspect after 202K miles, your plug wires or coil are shot. Once they warm up and expand, and you apply a load to the engine, a gap opens somewhere and bada bing bada boom, you got a spark miss. Spark miss means the fuel injected doesn't get burned that cycle, which loads the converter and you get a bad case of the gas smells.
You got air, you got fuel, you have a problem with fire. Process of elimination. swap coils, swap wires, see if it moves around. Get it warm, do a brake torque in the driveway (press brake pedal hard, and give it a good amount of gas until the vehicle wants to move). This will usually cause the miss to occur and make it more apparent where it is.
