Sup Guys, here on maui with one poor running Tacoma

V6 3.4 180k well maintained
2nd T belt @ 118k

Misfires started about two months ago, It actually started on cylinder 3, so I swapped coil packs from cylinder 3 with cylinder 5 and the misfire moved. I thought, great, that was easy, just a bad coil pack. However, now I'm getting misfires from cylinder 5 once again, and it's a brand new coil pack OEM.

The misfire has remained on cylinder 5, never returned to cylinder 3. for two months and around 600 miles.

Have replaced
plugs with nkgs, dual
plug wires OEM
replaced fuel injector (#5) OEM

Still stumped, anyone have any ideas.

I don't think it's the timing belt, what do you think? bad timing belt should give me multiple cylinder misfires

I'm thinking it's either fuel or spark

I have compression tester on order, got a meter on order, and fuel line pressure gauge.


Shootz, den anybody who uncovers my problem will get some fresh Lilkoi butter

Aloha

 

have you tried moving the coil pack back to 3? I realize its a new oem pack but just for giggles move it. If it stays at 5, i'm thinking maybe valve adjustment? You've cleared the codes since you replaced those parts right?

 

thanks for the reply,

yeah, I thought maybe I screwed things up. I cleared the codes and swaped coilpacs again, still missfires on 5.



I'm waiting on a fuel pressure gauge, just I can rule it out.

Anyone know what I should expect if I open these valves up. should I go ahead and get some shimes? I do have gaskets and washer gromets

 

See if you can get your hands on injector pulse testers. Basically tiny leds that light up when the injector fires. You'll be able to watch the pulses and see if they miss a blink. Have you done a compression test yet bro?

 

I'll check it out, the injector is new so I'm pretty sure that it's working

doing a compression test in the morning will update

 

I would lean towards a burnt or tight valve. Take the valve cover off and check the valve clearance with a set a feeler guage. If the clearence is too tight the valve will not fully seal properly (especially when warm) and will give you an intermitant miss.

You can also do both a dry and wet compression test (poor a little oil in the cylinder for the wet test). If the results are the same on both tests and the compression is low on the cylinder then its a leaky valve. Carbon on the valves from leaky valve stem seals often causes issues with valve clearance and can lead to a burnt valve or a valve that sinks into the seat slightly and looses clearance.

 

x2 for checking injectors even just swap #5 with another and see if it moves and SEAFOAM!!!!!

 

thanks 84, looking up valve specs now