I just replaced all the spark plugs on my 99 tacoma and am still getting a misfire... the thing is though the cylinder is not ALWAYS misfiring. sometimes it is sometimes it isnt.. new to yototech any help would be nice!!!

 

Did you replace the plug wires too? If not, start it up at night time and look for sparks in the wires.

 

What engine? Any other codes or just the P0301?

 

plug wires are new and its the 3.4L v6

 

then its your coil. Try swapping them out and see if that changes things.

 

Yea i would say coil too

 

i had heard that if it was the coil then i would have 2 cylinders misfiring? and remember.. its not a CONSTANT misfire. sometimes it runs just fine somtimes it comes up with the misfire

 

Any other codes or just the P0301?

 

Coils can be internaly defective and cause a slight to small prob. Replace the coil and see it it fixes it. If not we may be onto something deeper....

 

I'm having the same problem right now.
Injectors have also been known to fail, which is what I'm leaning towards.
First time it happened I was about 10 minutes into driving and it started miss'n like crazy, felt like complete dead hole. Misfire only lasted about 15 to 30 seconds then cleared up and ran fine for another 100 miles or so. When I got home I pulled a p0301 code. I swapped the #5 coil with the #1 coil and cleared the code. Next time I drove it I had the exact same short time misfire and cleared up again.
When I got home I found it's still cylinder #1. Checked freeze frame and found fuel trim at +14% when the code set, leading me to believe no fuel getting to that cylinder.
I've listened to the injectors and they sound fine, but it's not missing at this time.
My plan is to carry a long screwdriver with me, next time it miss's hopefully I can pull over in time to listen to the injector.

 

so i've replaced the Temperature Coolant Sensor, fuel filter, fuel filter screen, and spark plugs.

in the morning when i run the truck for the first time it doesnt misfire at all. its just after i turn it off and start it again.

also after driving on the freeway for about ~20 minutes the misfire goes away as well. so its not ALWAYS misfiring its just weird how it does it on a schedule

 

David, You could have a bad coil pack boot which would only affect the plug directly under the coil pack (not the plug on the other side of the engine). I had this problem about a year ago (except mine was on cyl. #3) and that's what it was.

SchooBaka, since you swapped coil packs and the miss was still in the same hole, I think you're on the right track looking for a fuel problem.

 

So im getting a code of P0301 on the v6 engine. its an engine misfire and not a specific cylinder as i just learned looking through my chilton.

 

No, it's specific to cylinder #1
http://www.ncttora.com/fsm/2000/Repa...ngine/dtcc.pdf (page 3)

Here is the FSM for a 2000 Tacoma
http://www.ncttora.com/fsm/2000/index.html use it instead.
Chilton's are more useful as confetti, I've found.

Are you getting just the one code?

 

All the things to look at.

 

yeah thats the only code im getting, and it runs so weird because in the morning, it runs PERFECT until i turn it off and start it again. its like when its totally cooled down and hasnt been run it runs great.

also after like 20-30 mins on the freeway the misfire goes away but comes back as soon as slow down to inner city speeds.

i just dont get it. ive changed the spark plugs, engine temp. sensor, fuel filter, fuel filter screen in the gas tank, swapped coil packs and didnt change the error code.

 

Find a multimeter and test the ohm range of the coolant temp sensor, since it runs good when cold.... does the light ever go off in the mornings?

 

well... it seems to run fine in cooler temps. when im on the freeway it actually rides perfect. im leaning towards the clutch fan... or something in the cooling system. the temp gauge never passes the middle but the engine seems really hot. im gonna try the thermostat also. we'll see if that helps.

 

I had a intermitent missfire on my 2002, 2.7L.

Turned out to be burnt exhaust valves in cyl 1 and 3, leading to low compression. I would check compression since its cheap to do and can potentially save you money by avoiding shooting in the dark.

 

Well the thing is i am just not sure if its something thats completely burnt out or whats happening, in the morning its runs fine remember