misfire in 97 taco .. where to start l?

[zukijames]

my buddy just bought a tacoma it has a 3.4 and now the check engine light is on.. he says when he took it in for emissions they said it has a misfire in #3 cylinder..

he changed the plugs wires .. where should he start next?

he says the compression is where it should be

any ideas would be super helpful thanks guys

 

[Greg]

Pull the codes, find out what tripped the check engine light.

 

[Spork]

Check wires make sure they are secure, if wires are good change the plugs. If plugs have been changed swap the wire with another one and see if it follows the wire.

 

[huntinkid]

correct me if im wrong but Usually when it throws a code its the coil??

 

[Spork]

correct me if im wrong but Usually when it throws a code its the coil??

Depends on what is causing it. Sorry just looked online and it appears that the 97 tacoma has a coil per cylinder.
http://www.oreillyauto.com/site/c/s...year=1997&make=Toyota&model=Tacoma&vi=1279009

So there isn't really spark plug wires, I would check the connection on the coil and if it is secure swap the coil with another one and see if it follows the coil. All this assumes your spark plugs are good. I'm not sure what your buddy swapped because there isn't spark plug wires unless he's swapping the coil boot.

 

[gorillaxj]

3.4L has 3 coils. its a waste spark system. On the 3.4L its most likely the plugs as they are 30k mile plugs and it seams like no one changes them that often, they also need the dual strap electrode or it will cause a miss-fire. I would only run denso or NGK factory style dual electrode plugs. it is also semi common for the injector to plug up with higher mileage. in the 6 years I have been at Toyota I have only replaced 1 coil pack on a 3.4l, not common.

the p0303 (cyl 3 miss-fire) is set due to the cyl 3 timing of the crank shaft being slower then the other cylenders (meaning it not pulling its own weight) has nothing to do with the coil, or plug, wires related, just fyi. there is a code for the coil, it would be a p0353 if it was a code for the coil. To eliminate the coil swap it to another position and see if the miss moves to a new cylinder. if it does its the coil.

Since he just bought it I would replace the plugs with new correct style, and check compression while they are out. I would also flush the injectors(90% of the time cleans out a plugged/bad injector) I would also replace the wires (but he already has) and clean the MAF sensor with some electrical safe cleaner. just my 2 cents.

 

[zukijames]

to be honest im not sure either.. i think it was one of those i say well did you try this and he doesn't wanta look dumb so he says yes..

maybe tomorrow i'll ask if he checked the blinker fluid and replaced the muffler bearings

 

[Greg]

Without pulling the codes, your just throwing parts & money and the problem, hoping that you'll get lucky.

 

[zukijames]

yeah .. he says he pulled the code.. and it said misfire in # 3 haha tomorrow i might go pull the codes for him . he was rude to my gf lastnight after this post though so probably not haha

 

[SLC97SR5]

I've found the 3.4's to be picky about factory parts. No Bosch plugs or Autolites, steer clear of aftermarket wires. The plug wires have a date stamp on them so it is easy to identify original wires. There is a resistance value given in the FSM for verifying the coil health, it is pretty subjective to temperature and will really only identify a grossly out of spec coil. Because it is wasted spark a code would also accompany the other cylinder but as already mentioned the coils are quite reliable and are seldom the cause.

X2 on the injectors, a can of SeaFoam or Techron in the tank and hard run at WOT will usually clean them up pretty good.