PO305 Cylinder 5 - misfire (solved)

Probably be better off taking everything related off and cleaning checking gap Apply grease. Running a leak down and compression check.

 

Yea, I agree. My thought is maybe it's simply bad gas. I don't think they sell much premium at that station. It could be old or contaminated. Saying that, bad gas would probably not be causing a misfire on Cylinder 5 only.

 

Any chance you put to much antiseize on the spark plug? I may have done that once and it definitely caused misfires.

 

Nope. Didn't put any on, so I can guarantee it's not too much.

 

Is this what you are talking about? https://www.napaonline.com/en/p/BK_7001006

 

yes

 

Ethanol won't fix anything. Ever. Unless you have an engine built to run alcohol it is always going to be garbage fuel. A mix is OK (but still sucks) but I would not go out of my way to run alcohol. Nothing in these engines likes it.

 

Got a test kit and it shows no exhaust gas in the coolant system. Had a little trouble getting the test done, kept getting coolant into the tester. Finally figured out it was getting sucked out of the overflow reservoir. Disconnected the overflow and plugged the hose. Then it worked, and I didn't get any coolant in the tester.

Test fluid stayed blue.

 

I use an old turkey baster and pull some of the fluid out before doing the test. Then just pour it back in the overflow when you're done.

 

You said you checked the spark wire? If not Can you swap wires with keeping firing order the same?

https://www.yotashop.com/fuel-injec...unner-tacoma-tundra-fuel-injector-fnj9-62040/

https://www.fiveomotorsport.com/1999-02-4runner-2000-04-tundra-1999-04-tacoma-34l-6-cylinder/

https://www.lceperformance.com/5VZ-V6-Equalized-Fuel-Injector-Set-99-04-p/1062211.htm

 

No, I did not check the spark plug wires for two reasons. First they are only a year or two old. Second, and more imortantly cylinder 5 is on the side with the coil pack. Spark to that cylinder does not flow through a wire. The wires just take spark from the cylindes on the passengers side over to the cylinders on the drivers side.

Thanks for the links. I am thinking it must be injectors. I will try cleaning them first. Also after I clean them I will swap them around. That way if I still have a misfire related to a bad inkector it would follow to the new cylinder and verify that is the problem.

 

Get them professionally cleaned and flowed so you have a matched set. I have used witchhunter.com for decades, dude does great work.

 

Thanks for the suggestion, but my truck is a daily driver. It would be a major hassle for me to be without it for the time it would take my injectors to do a round trip through snail mail. I'm going to tear into it today and clean them myself. I will make sure the one on cylinder 5 goes back in a different cylinder. That way if I still have a misfire only on cylinder 5 I know it's someting else.

 

Success! It's not fixed, but I now know exactly where the problem is. I cleaned the injectors on the passengers side. The misfire was in cylinder 5 so that is the main one I wanted to get to, and the ones on the drivers side are a little harder to get to. After cleaning, I put the one that came out of cylinder 5 on cylinder 3. I still have a misfire, but now it's in cylinder 3. Problem found, bad injector.

Now to get a new set of injectors ordered. I have read that you don't want to change just one, plus they are originals so they have over 200,000 miles on them. It runs good enough to get me where I need to go while waiting for the new injectors.

 

If you haven't ordered them yet, you may want to consider using rebuilt injectors. If so, try MotorWest in Canoga Park, CA. Phone = 747 888 9768. You'll save a bunch of money and they do an excellent job of cleaning. replacing seals, and testing before shipping anything out.

 

I ordered them yesterday. I did get them from MotorWest. I got these https://motorwestperformance.com/product/upgrade-for-23250-62040/

 

Update: Put the injectors in two days ago. Runs great, and no more misfire codes.

 

Awesome! I would suggest buying a used but flowed and tested set to replace yours since you really cant completely clean them at home. It is amazing what a matched set of injectors will do for an old engine. Well worth the expense and frankly it isn't too expensive. Especially when you are trying to get a few more MPG out of a couple decades old engine.