Intermittent Single Cylinder Misfire

Mice can be a problem or if you live some place where there is a lot of moisture that can also cause a problem. When you pulled the spark plug out of cyl 6 did you look inside to see if there is any residue and or anything that looks out of place compared to the others?

Really, it's just too hard to diagnose online with out actually being there to see and hear it in person. Your best bet, which you have already started on is by checking the easier things like the spark plug, spark plug boots, wires, electrical lines, etc.

As someone mentioned before, try swapping spark plugs, injectors from the other cylinders. It is very rare that a spark plug would misfire and most of the time it's the plug wires or injectors that are at fault, but if there are rodents chewing lines and nesting, that's never a good sign.

 

I looked and looked. I actually couldn't find it either.

You're right about the service-ability, per Toyota. I read years ago on the URD website: http://urdusa.com/Fuel-Upgrades-Fue...uel-Pump/Filter-Upgrade-Kit/product_info.html

and have basically followed that. I feel a bit foolish having gone by that all of these years. However it is actually more foolish that Toyota doesn't even have a service interval on their 1GR fuel filter.

Think about that. Would you drive a "life time" on an air filter? How about a the oil filter? "Life time" is rather vague anyway...

It is just common sense that all filters be service-able.

 

black stuff is gas after 29,xxx miles.

In these pics you can see we modified the fuel bowl to work with the upgraded fuel pump on my truck. For increased fueling and the ability to service the fuel filter at a sensible interval.

 

I remember that day. That was uncharted territory when we did that. Interesting how much larger the 1GR T4R pump is compared to the 1GR Tacoma pump.

 

So if I am understanding this correctly, 2nd gens do not have an external fuel filter that is bolted to the block some where?

Just to be clear, OP is having a single issue with his motor, not the whole thing.

 

Both of those statments are true. There is a filter on the pump and a line out of the tank and that isit, unless you upgrade fuelpumps and add an outside filter.

The #6 cyl is the only place that I have a problem.

The plugs and fuel cleaning helped a little bit, but the misfire continued. Toyota diagnosed a bad iginition coil on the #6 cylinder and wanted 426 dollars to repair it.

Instead - I ordered the part from RockAuto for 60 bucks and I'll bolt it in tonight....Hopefully it'll be all set after that. RockAuto RULES...If you need smple parts for repairs - Check them out and make sure to use (and share) the discount codes...

 

Might be. Might be the angle and lighting...I had a .09 spread on gaps last time I did plugs IIRC.

 

Keep us posted.

 

Will do....I was pondering picking up a spark tester, but I have the coil in hand now - So I'll do the swap and go from there. Hopefully that'll clean it up

 

Replaced- Seems to have fixed the problem to me - Wife thinks it's still rough but we'll see about that.

 

Even after resetting the battery?

 

Yeah...I let the whole system settle. But even before a battery reset I fired it up and did nit notice the hiccup in the start or the rough feel. I think the wife mighta been imagining it...

 

So she wasn't imagining it. It got worse, was taken to the dealer again. they blamed the NEW coil being faulty and had her buy another from them. I had her bring it home, swapped coils around, and the problem remained on the #6 Cyl.
Took it to another shop. They cleaned a chunk of carbon off of the plug and said they should be good to go. Still not right. They took it back, did a fuel injector service, and it seems to have worked out the problem.

It makes sense that an injector was some trash in it would manifest that problem - Flooded cylinder on start up w/ the extra carbon on the plugs makes for rough starts and proper operation under load.

Hopefully they are right and this is the end of it. Next will be the water pump....

 

Luckily the water pump is very easy to do. Truly.

So still running ok?

Seeing as how hard it is to install an aftermarket replaceable fuel filter, I assume that is still basically out of the question.

 

Helped my neighbor with his Camry last weekend. Was having a misfire code, and car wouldn't even stay started.

Thought he had bad gas that was full of water. Ended up being his fuel filter was full of crud after 150K miles.

This is what the fuel looked like.



^^^ That is terribly nasty.


Changed out the filter, and the car would start and run. Also ended up having a bad coil as well. So we put a new one in as well.

But let it be known, that the car wouldn't even run until after the filter was changed.

Figured that you would like to see that.

 

A shit ton of testing and wondering and off-again/on-again CELs...It appears there is a very small coolant leak into the #6 cylinder.

Likely means a Master rebuild kit and a few grand down the drain...=/

 

Were hydrocarbons found in the overflow, or radiator coolant?

Are there bubbles noticed while the engine is running?

 

Coolant in the cylinder after running and then sitting over night. Also found a small leak in the radiator while they were doing the rebuild.
But it's back and right as rain now.

 

My '03 started this... New coil pack fixed it.