Cyl 4 misfire adventures...pls help

[mgcorreia]

I have a 4runner with 207kmiles, 4cyl, manual.

I've been pulling my hair out trying to fix this constant cyl 4 misfire. I replaced the spark plugs and the wires. A month or so later cyl 4 starts misfiring again. So I run Seafoam through the vacuum lines and pour some in the gas tank to clean up a possible clogged injector. Then I pulled off my coil pack and had it read with a multimeter at Autozone. They said it was bad, so I swapped it out... cyl 4 still misfires. I called Autozone, they said the seafoam probably mucked up the spark plug in cyl 4 and I should replace it. Instead I swapped the spark plug in cyl 4 with the one in cyl 1 to make sure... and you guessed it, cyl 4 is still misfiring. What should I do?

 

[snowninja]

when this happened to me it was a bad fuel injector.. had it replaced and no problems since..

 

[mgcorreia]

thought I could cross off the injectors because I cleaned them with seafoam...but I guess seafoam won't fix them if they're bad all together. Would you swap them all out or just the one?

 

[amalik]

definitely just the one IMO... OEM fuel injectors are not cheap.

 

[snowninja]

agreed just do the one. the shop wanted to do all of them "while she was opened up" but I had no codes on the others so I left them, that was about 35k miles ago and all is still well..

 

[mgcorreia]

Do you guys know where's a good place online to buy a refurbished fuel injector for my 4runner? The new ones at autozone are like $100.

 

[snowninja]

might be a long shot but you could try to find out a local shop that does rebuilds. I know there is a place near me that rebuilds oem diesel injectors and they are very reputable across the diesel forums (I also have a diesel truck).

to be honest I don't even know what brand my shop used on my 4runner they probably got it from napa or similar.

 

[mgcorreia]

So before I throw more money at parts, I decided to swap my fuel injectors and see if the code moves. On a 4cyl the fuel rail is easy to get to. Interestingly, the car is running smooth now and not misfiring....not sure what to make of that

 

[BrianSD_42]

, they said the seafoam probably mucked up the spark plug in cyl 4 and I should replace it. Instead I swapped the spark plug in cyl 4 with the one in cyl 1 to make sure... and you guessed it, cyl 4 is still misfiring. What should I do?

I believe I read here that seafoam will affect your spark plugs and many people. Replace them after doing it.

So I'd suggest you start there.

Remember ... Only Toyota approved spark plugs. Do a search here for which ones or go to the dealer. Do not use non-Toyota spark plugs (or injectors for that matter).

 

[Drcoffee]

RockAuto Parts Catalog has GB reman'd injectors for around $30. You can buy 4 for the price of one at a local parts store and get them all flowing at the same rate. Make sure to buy new o-rings too. I think mine came with them but its better to be safe.

 

[CaptainGiggity]

My friend's 4cyl 4runner had a similar problem and it ended up being a vacuum leak, have you looked into that possibility?