#2 Misfire

engines
lights
pontiac
misfire
montana

#1

My 2001 Montana engine light is on and i can’t get it off. i have replaced plugs, wires, injector, coil, control module, the light is telling me #2 Misfire


#2

is the engine running rough? esp. at idle? or not. It could be a bad indication not an actual misfire. disconnect the lead to the plug and see if it changes the way the engine is running, if not, you probably dont have a missfire, all other things being equal.


#3

correction, if rough after disconnect, prob no missfire.


#4

Next step is to do a compression test. Unfortunately you probably have a bad valve or bad piston rings. On a 2001 Montana this means off to the junkyard, I am afraid. For your sake I hope I am wrong. Good luck.
(Same problem killed my Honda this spring)


#5

engine looks and sounds the same after disconnect of #2 wire


#6

the idle is not as smooth as my wife’s 2002 Silhouette.


#7

then that is too bad, because I fear you must look to the next post below, and get a compression test done on this car.


#8

i will do that, thanks


#9

I agree that a compression test is a good next step, but…
Have you verified that you are getting spark to the #2 plug? Perhaps the PCM is not driving that coil or the wiring is damaged.
Have you verified that you are getting electrical pulses to the #2 injector? Perhaps the PCM is not driving that injector or the wiring is damaged.


#10

Yes I do have spark to #2 wire. And I can hear #2 injector working, but I will try to get a reading. Would the compression test tell me if its in the head or block?


#11

A leakdown test can be used to indicate the problem area.


#12

And the mileage is??


#13

130,000mi