Hello, I have a misfire in cylinders 3 and 4

[Odin_]

I have a 99 4runner SRI V6 3.6L engine, took it for a drive, 400 miles in I got a CEL. Codes areP0300, p0303, P0304. I'm thinking the culprit would be a bad ignition coil, I smell gas when it's a cold start up, goes away after its warm. I was having a hard time trying to find a thread with testing/removing coil packs. Can someone help me out? Also anything else I might check to solve this misfire issue would be greatly appreciated, this is my main vehicle atm. Has 330k miles on it.

 

[RedSled]

Did you look at the plugs?

 

[Odin_]

I have not, I just plugged in the reader right after I got home from work, I'm getting ready for school right now. What should I look for when I look at them?

 

[RedSled]

I have not, I just plugged in the reader right after I got home from work, I'm getting ready for school right now. What should I look for when I look at them?

Burnt electrodes, covered in oil, cracked porcelain, condition of boot. If all is well you could switch the coil packs to see if your problem follows.

 

[Odin_]

I pulled the number 3/4 spark plugs and they were good condition, I didn't see any cracks, they weren't fouled or dirty. The plug ports were clean, a little dusty. Boots on the packs didn't have any major wear. Spark plug wires are original 99 wires =/ i changed the plugs (Densos) about 10k miles ago. I swapped the packs to the 1/3 side. cleared the engine code and now it's not throwing up a CEL, it ran more rough when I switched them, drove for maybe a mile. Can I check resistance on the packs?

 

[Doc2012]

Cracked heads. 3 and 4 are the trouble zones

You have to remove heads to see cracks

Why would you jump to cracked heads?

Has he mentioned anything about overheating or anything like that?

Oh, NOPE?

You're jumping the gun.


[MENTION=120909]Odin_[/MENTION],

If you can give us more information that would be helpful.

Any other codes?

HAS the truck been over heating, or is it just a misfire issue?

Have you checked the wires and the coil packs?


Another thing that can be causing the misfire is the fuel injectors.

If those are clogged or bad, they will not put the right ammount of fuel in there, causing the misfire code.

Here's a video I did for the testing of the fuel injectors:

<iframe width="420" height="315" src="https://www.youtube.com/embed/drGaZNky2Q4" frameborder="0" allowfullscreen></iframe>


And just FYI:
When I blew my HG, I drove it for a good 10 miles, on and off. No warping or cracking of the heads.

 

[gamefreakgc]

Don't forget about the spark plug wires since if the wires are bad, doesn't matter how new your plugs are. If they are original, I'd say it's time to replace them. You can also check the resistance from end to end on the wires if you're on a budget. Rock Auto sells DENSO wires for pretty darn cheap though so you'd have to be in dire straights not to be able to afford new ones.

You can also try running a double-dose of injector cleaner through the tank, or seafoam if you like that better. If it's a clogged injector it might help without having to tear it down.

 

[krenaud33]

You have to remove heads to see cracks

Pretty sure he meant the spark plugs didn't have any cracks.

 

[LookAtThatDog]

If switching the packs made any difference at all, I think you can safety say it's the packs.

 

[Odin_]

So after my drive last night with how rough it was running and i didnt want to wait for a CEL, I decided to put the packs in the original order. On my way to school today I drove maybe 50ft and got a CEL, it was just the P0304 when I got to school, I just got home and looked at the code and the P0300 was with the P0304, no more misfire in cylinder 3 tho, and it ran a lot smoother than it has today. And no, no over heating, no leaking oil or water around. I would like to check the packs but I lack the knowledge, I can't find much on testing them either. It what brought me here in the first place xD my wires are orginals, I know those need to be replaced, and yeah I am very much on very very strict dollar, it's either wires, a coil pack or a fuel injector till I can find a 2nd job, if Craigslist follows through I'll have $300 to give to my truck. I ran some royal purple fuel injector cleaner for my 400 mile drive, it helped a little but the problem and engine shake was still persistent., not as dramatic, it was worse once the trest mentioned wore off. And btw I have a Bluetooth OBD2 scanner, I'm using torque for the app. Is pro worth the extra 5?

 

[Odin_]

And thanks for all the replies everyone! I really appreciate your guys' time ^_^ :cheers:

 

[DED&DED]

Sounds like it may be one of the three ignition coils-each is dedicated to 2 cylinders. In my experience if one goes the others are not far behind it.

 

[JCavatar]

Having similar issues, random misfires had codes P0300 P0120,P0130 and P0133. checked plugs, and they were way out of gap, but 6 looked rough. waiting for new plugs to come in.

However i was getting codes for TPS, and o2 sensor 1 bank 1. I replaced the TPS, runs a little better, but at higher speeds in 4th and 5th gear, its sluggish and thats when the CEL flashes.

Returned to get codes read, misfire on 6 remains P0306, but new code popped up P0505 Idle air control valve control circuit.

The o2 sensor didnt not apear at this time.

Would have made my own post but page wouldnt let me.

 

[IBallEngineer]

I pulled the number 3/4 spark plugs and they were good condition, I didn't see any cracks, they weren't fouled or dirty. The plug ports were clean, a little dusty. Boots on the packs didn't have any major wear. Spark plug wires are original 99 wires =/ i changed the plugs (Densos) about 10k miles ago. I swapped the packs to the 1/3 side. cleared the engine code and now it's not throwing up a CEL, it ran more rough when I switched them, drove for maybe a mile. Can I check resistance on the packs?

Yes you can!

Here is how to do it.

http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/ig5vzfe/ignsy/ovi.pdf

 

[Odin_]

This is exactly what I am looking for!! =)) what a wonderful gem of information, thank you!

 

[Odin_]

I checked the resistance on my coil packs. 2 outta 3 tested both for 1.5ohms on the secondary, 13.5 ohms on the primary. This is cold. Secondary is a half ohm off spec on both, I have a brand new one coming in tomorrow, I'll measure them against that, my spark plug wire measured at 16ohm, also within spec. I have new ones coming in as well. Soo I guess I should measure the resistance on the fuel injector ports?

 

[Odin_]

Sorry have that backwards, 1.5ohms on the primary, 13.5 on the secondary.

 

[TheDurk]

This is exactly what I am looking for!! =)) what a wonderful gem of information, thank you!

Factory Service Manuals are like that...

 

[Doc2012]

I'm leaning to a bad injector.

 

[IBallEngineer]

I'm leaning to a bad injector.

I'm leaning to a bad hip, but it could be sciatica!