Drain Coolant to change Fuel injector?

Reposting this as I realize my original post title was not clear.

I am getting a code P0306 on my 2005 Tacoma. I have replaced the plugs and moved the coil pack from cylinder 6 to cylinder 1 but the code still points to cylinder 6. The truck will stumble/miss at start up after it has been sitting for a while, but then once it has warmed up, it smooths out. I have checked the coolant for oil and the oil for coolant and there does not appear to be a head gasket issue as both the coolant and oil look normal. I am thinking fuel injector (I am at 172k miles). I am currently running fuel injector cleaner and tank of 93 octane through it hoping that this is just a dirty injector.

Now to my question: I have looked at the FSM and it indicates that the cooling system should be drained when changing out the fuel injectors. I have searched to see if there is any information on the site about changing out the injectors and the link below is the only thing I have found that is relevant. In looking at the link, I don't see anywhere that draining the coolant is required to change an injector. Am I missing something or is the FSM incorrect? While I am not an auto mechanic, I am fairly competent when it comes to mechanical repairs. I just don't want to drain the coolant if I don't have to and also make sure I have the tools/materials available to complete the job once I have started.

http://www.tacomaworld.com/forum/tec...tallation.html

 

If I had to guess I'd say the manual probably suggests total removal of the throttle body which apparently has a coolant hose running to it.

 

Seafoam it :d

 

u dont have to drain the coolant. just dont disconnect the hoses going to the throttle body

good example right here. this was after removing supercharger but u can see the coolant lines are still connected to the throttle body and the fuel rail right there on top

 

Thanks! I am running a can of seafoam through the tank right now. If that does not do it I might run one through the brake booster vacuum line. If Ihave to tear it down that far I am goibng to do all 6 injectors. The pic was very helpful. This is what I love about this forum.

 

Yeah I had a huge issue lately and found out it was caused by a vacuum leak from the catch can I had installed

 

Update: After two full tanks of fuel injector cleaner, the truck seems to be running 80% better. I got a block tester and checked the coolant for exhaust gases and that checked out OK. So, I bought 6 injectors from a forum member with 100k fewer miles than mine have and will change them out next (figured if I have to take it down that far may as well do all 6 while I am there). Will post results after I am done.

 

Any pics and results?

 

By the time I could set aside time to change the injectors, the problem went away and the truck is now running fine. Only thing I can think is that I gassed up at a gas station that had just opened and I got some trash in the gas tank. At this point, if it ain't broke, I'm not going to try and fix it.

I was afraid I had the dreaded head gasket issue that was so common to the early 1grfe V-6's in the 4Runner and Tacomas. Of course, it could just be that the weather warmed up and the gasket has expanded to where it is not causing an issue right now and once it cools down, I may be right back where I started.

I am really hoping it was bad gas because the best quote I was able to get on rebuilding the engine was $4800. With 181k on the odo, I don't feel comfortable just doing the top end ($2200. from the same place). I figure if I have to do it, I may as well do the whole enchilada and get a 4 yr/48,000 mile warranty on the engine. Again, hopefully it won't come to that.