Toyota How do you know if a coil pack is bad?

[Spork]

I got a 2.7L (4cly) Tacoma and I'm wondering if I got a bad coil pack. Took it in to checker and got a P0302 code (mis-fire cyl #2). I swapped the spark plugs out and the problem still is there. I pulled the truck in the garage and you can smell unburnt fuel from the exhaust. Driving it down the road it feels like it's missing, struggles to get to 4th gear and occasionally it will feel like it has power for a second before it falls on it's face again.

Other random items in case they are needed:
The 2.7L has 2 coil packs (one for Cyl 1,4 and the other for 2,3) there is no distributor.
I haven't got a timing light or spark tester (probably ought to get one).
The truck has about 160K miles.

So is there an easy way to test the coil pack? Found something online that said you should have 9.7k-16.7 Ohms between the terminals and I show 13 but the site also indicated that it's not a definitive test and is just a secondary resistance test. (called checker and they indicated that they do not test coils).

 

[DOSS]

FSM should have specs on how to test the coil on an Oscilloscope

 

[Kiel]

Swap the packs on the truck, clear the code and see if the cylinder its missing on changes

 

[Spork]

Bought a spark tester and hooking up to #2 the light looks the same as plugging into #1. (amber strobe light) Guess I ought to test the other 2 cylinders just in case one of them wound up with a bad plug.

Just a secondary question... Is it possible for a coil to be bad and still light the spark tester? (sends voltage but at a reduced output?)

 

[4554x4]

Swap the packs on the truck, clear the code and see if the cylinder its missing on changes

X2. If the missfire doesnt change cylinders, it could be a compression problem or a bad or plugged injector. How hard is it to swap injectors on this engine? You could also swap them like the coilpack. see if the problem changes cylinders.

 

[Kiel]

Bought a spark tester and hooking up to #2 the light looks the same as plugging into #1. (amber strobe light) Guess I ought to test the other 2 cylinders just in case one of them wound up with a bad plug.

Just a secondary question... Is it possible for a coil to be bad and still light the spark tester? (sends voltage but at a reduced output?)

Yes I see it all the time, weak spark or inter. spark, especially when they get warmer. Just swap them and see if the light switches cylinders since you have no real way to test them.

 

[SLC97SR5]

Yup, I just saw this on a 5VZFE. The coil packs ohm'd good but under load the center pack was misfiring, especially under humid conditions.

Many web sites carry the factory packs and Menlove Toyota and Mark Miller Toyota offer a U4/Wasatch Cruiser discount.

DO NOT purchase the parts store garbage, buy the OEM coil pack.

 

[Karnage Fab]

i have both coil packs, in good working order, came off a cash for clunkers truck for $45 shipped for the pair

 

[Spork]

i have both coil packs, in good working order, came off a cash for clunkers truck for $45 shipped for the pair

PM coming your way.

 

[mmtoyota]

I just checked with our parts department. Appears to be $92-ish for new with the discount mentioned earlier. Give 'em a call you're interested. Looks like you are okay with used though.

Mark Miller Toyota Parts
801-532-4456

Chad J.
Mark Miller Toyota

 

[xj2]

Did we get a confirmed fix on this thread?

 

[Spork]

Did we get a confirmed fix on this thread?

It was the spark plug wires, which is funny because the ones I replaced were only a couple years old.

 

[ricsrx]

Ok, my 99 runner,3.4. I have a miss after it warms up, replaced wires and plugs, no change, I can ohm out my primary but the secondary is an open, on all 3 of my coil packs........ I also purchased a new coil, do in need to reset the computer after I relocate it in to a new position? I have swapped it into all 3 positions with no change. also I have read the codes and in shows a cylinder miss fire and the codes followed the cylinder when swapped but installing a new coil has not stopped the problem. any help would be great Rick

 

[Spork]

Have you pulled the codes? If it's something like a P030# it's a misfire in whatever cylinder the last number is. If it stays consistent with a single number that's the one to look at. If you have one that's bad enough it may trip others so the numbers are randomized. There could be other things like a clogged fuel filter that could also create the same 300 code.

I would reset just to see if any new codes come up or what they are. Does the 3.4 have 2 cylinders per coil pack like the 2.7?