missing on cylinder 3

[daot19]

My montana is not firing on cylinder three. I have replaced the ingnition coil and the ingnition control module, wires, and plugs. what else could it be? Confused.

 

[melsg5]

do you have a check engine light on? do you know if the injector is working? have you done a compression test?

 

[msmith1956]

Here's a link with info on troubleshooting a misfire on your vehicle.
http://troubleshootmyvehicle.com/gm/3.1L-3.4L/troubleshooting-a-hard-to-diagnose-misfire-1
Please let us know what you find out.

 

[Steelcity]

Could it be leaking antifreeze into the cylinder and constantly fouling the plug ? How does #3 plug look ?

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[JSD]

I hope this doesn't scare you too much but about a year age my 2003 Montana had the check engine light on with cylinder #3 misfire. I replaced the plugs, wires, and coil pack and still the same, then I did a compression test and found that cylinder #3 was about half the compression of the others. I pulled the intake out so I could get at the valve cover, removed the valve cover and both of the rocker arms from cylinder #3 fell out the back of the engine. I ended up pulling both heads out of the van, drilling out all 12 rocker arm bolt holes and installing Time-sert inserts in them. Out of the 12 bolt holes only 2 felt like they had any meat in them when I drilled them out. While I had it apart I put all new gaskets and seals in everything that was removed. Now other then a random slip in the transmission it drives like new.

 

[Steelcity]

Wow . That's the year van i have. How many miles did ur van have when this happened ?

 

[JSD]

My van had approx. 187,500klm (116,500miles) when it popped.

 

[JSD]

If your going to pull your van apart, I recommend you get a Haynes manual or similar, and have somewhere covered to work on it, and mark everything. I started pulling mine apart over the Christmas holidays, and then after the holidays spent around 1.5 - 2 Hrs every evening working on it. I completed it near the end of February. The biggest part of the job is getting it apart without breaking any seized bolts (I broke 4 on the rear exhaust, couldn't get the impact back there).

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