Cylinder 3 & 4 Misfire

[Doc2012]

Ok guys. Here's one for ya.

Blew my HG. With the help of [MENTION=59542]Singtoe[/MENTION], we were able to get it taken care of and fixed.

All said and done, I'm throwing three codes.

P0300 Mulitiple Misfire, P0303 Cylinder 3 Misfire, P0304 Cylinder 4 Misfire.

Now, I've read some threads about cylinder 3 misfires being cracked heads. I had my heads cleaned, inspected, pressure checked, and shaved, and they came back good to go.

I changed the packs on cylinders 1 & 3, with no change to with the codes.

The wierd thing is, when I'm on the interstate, the code goes away. When I give the truck gas to get up a hill, or pass, the code comes back. CEL FLashing, the whole 9. Then it goes away again.

My next step is to pull the plugs, to see if the code jumps.

New wires, new plugs. Changed the packs around to see if the code jumped, but stayed in the same spot.

Going to do a compression test as well.

Anything I might be missing?

 

[SV_Dude]

I'm new to these engines so I can only throw a rough suggestion. What on these engines looks for the misfires? Have you looked in the fsm for troubleshooting? Odds are you're chasing an electrical gremlin unless you get lucky and find bad spark plugs.

 

[kball]

While you were redoing the head did you have the injectors checked out?

 

[Doc2012]

Part of me is thinking it might be the Knock Sensors gone bad, considering they're both on the #3 & #4 Cylinders. I HOPE not, but it IS a possibility.

I don't want to have to pull the entire intake off to check those bastards out.

 

[Doc2012]

While you were redoing the head did you have the injectors checked out?

I was thinking this, BUT injector 4 is brand new.

Injector 3 isn't though. This could explain #3, but not 4.

CYL, 1,3,5 and 6 all have the same injectors. Cyl 2 & 4 are new injectors.

 

[PitbullRescuer]

If it's coming up under load, I'd suspect its a fuel problem too. Are the new injectors OEM?

Start with easy things:
Pull and check the plugs
Compression test the engine while the plugs are out
Make sure all the injectors are properly hooked up. The harness can sometimes be loose but look connected
Make sure the wire harness for the injectors didn't get damage while it was apart.
Clean your MAF & Throttle Body

 

[SV_Dude]

Part of me is thinking it might be the Knock Sensors gone bad, considering they're both on the #3 & #4 Cylinders. I HOPE not, but it IS a possibility.

I don't want to have to pull the entire intake off to check those bastards out.

I think that if your ecu sees a bad knock sensor that it would throw a code accordingly.

Does the engine run good or does it sputter?

 

[Doc2012]

If it's coming up under load, I'd suspect its a fuel problem too. Are the new injectors OEM?

Start with easy things:
Pull and check the plugs
Compression test the engine while the plugs are out
Make sure all the injectors are properly hooked up. The harness can sometimes be loose but look connected
Make sure the wire harness for the injectors didn't get damage while it was apart.
Clean your MAF & Throttle Body

With the exception of the plugs and compression test, this has all been done. I checked and reckecked everything before putting it back together.

I think that if your ecu sees a bad knock sensor that it would throw a code accordingly.

Does the engine run good or does it sputter?

It's tough to start up. When she does start, it seems to idle a little rough. Some shaking.

I'm really hoping something simple, like plugs, but the way my luck is, it's probably not....

 

[GSPRunner]

My money is on an injector

 

[Doc2012]

My money is on an injector

You mean 2 injectors? Cyl 3 & 4?

 

[Singtoe]

We need to do a compression check. Just to make sure you didn't break any rings from the overheating issue.


Once the Compression check is done. Swap out fuel injectors with other cylinders and see if the code stays the same.

Check the boots and high tension leads from the coil to to the plug . May be even replace them.

Swap spark plugs from one cylinder to another and see if it CEL moves.

 

[Doc2012]

We need to do a compression check. Just to make sure you didn't break any rings from the overheating issue.


Once the Compression check is done. Swap out fuel injectors with other cylinders and see if the code stays the same.

Check the boots and high tension leads from the coil to to the plug . May be even replace them.

Swap spark plugs from one cylinder to another and see if it CEL moves.

great minds think alike. Just wanted to make sure I had all bases covered.

 

[LittleCaesar]

Did you change out the O2 sensors after your swim last year?

My friend had a misfire 300 on his 96 T100. No specific cylinders. It turned out his fuel pressure regulator had failed. He pulled the vacuum line and gas came out. Takes two seconds to see.

I'd say injectors too. Ohm them out and even pull the connectors with the 4runner running to see if there is a real change in idle.

How is the T-belt btw?

 

[Doc2012]

T-belt was done same time as the HG.

O2 sensors are new.

Leaning toward injectors or plugs.

Good to know about the regulator.

Thanks for that.

 

[LittleCaesar]

If Singtoe has the specific banjo bolt, check fuel pressure at idle and under load if the compression yields nothing bad, which I believe it will.

It may even be a slowly dying fuel pump.

And check the wiring in case some critter has crawled up into the bay to make a home, etc.

 

[blue dog]

Just went threw this same thing. Truck had good compression in all cylinders, injectors all good, among a gang of other things that were all good. failed leak down test in cylinder 3. Bad head gasket.
Mark your radiator res and see if she is eating any fluid. Mine was so minimal that you did not notice fluid loss, but was enough to make the truck miss and misfire. Luckily no cracked head or block.
I have never had good luck with it, but some have good results from blue devil head gasket leak repair stuff.
I flushed my engine 3 times to clean her up for the blue devil stuff, and before i could complete the task, my water pump took a POO right then and there.
Anyway, hope it is not a head gasket and something cheap.
I just purchased a used 5vzfe complete with ecu and 60k on her from a 99 tacoma 5 speed for a grand, and will give her a heart transplant. Luckily i have a gang of vehicles to choose from to drive every day, but none are as fun as a 5 speed 5vz

 

[blue dog]

If Singtoe has the specific banjo bolt, check fuel pressure at idle and under load if the compression yields nothing bad, which I believe it will.

It may even be a slowly dying fuel pump.

And check the wiring in case some critter has crawled up into the bay to make a home, etc.

Good call on this above. check fuel trims, compression and leak down.

Really can be any number of things. coil packs, ignitor ground, MAF, plugged cat, o2 or fuel air mixture sensor. Start with the things you do not need to buy parts for.
Good luck, i feel your pain.

 

[Doc2012]

Little update on this.

Did a compression check. According to the FSM, the pressure should be a max of 174+PSI, with a minimum of 145PSI, with a difference between cylinders of 15PSI or less. Numbers are as follows:

1-150
3-105
5-165
2-190
4-195
6-195

Those numbers are making me think that my valves are bad. Got a pretty nice tick coming from #3, so I'm thinking I might just have to rebuild the heads.

Problem is that I don't want to do that and then find out something else is wrong. (Seems to be the way this is going lately.)

I added a couple tbsps to #3, and the pressure jumped to 120 PSI. That could signify bad rings.

ALSO, sometimes the #4 goes away, and it's just a #3.

I'm at a loss here guys. If I could find a 3.4l for cheap, I would just get it and put it in the truck for now, then rebuild the one I have. Maybe when I get a second car I'll do that; but for now I'm thinking about doing a valve job.

Anyone give me any other options as to what this can be, please feel free to pipe up. I'm about out of options and patience.

 

[Singtoe]

Here's that picture of #3.

 

[LittleCaesar]

Look for another engine, if yáll want a project, rebuild it.

Or add another 2UZ to the fleet.