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2012 GMC Terrain V6 Misfire

3K views 4 replies 3 participants last post by  rbarrios 
#1 · (Edited)
Bought this car with 13,000 miles originally and ended up having to have #4 injector replaced at 42,000. The Terrain is currently at 89,000 miles now and I’ve had two misfires. They both have happened between 30-45 mph. In this speed range the car will act like it’s struggling then it’ll throw the blinking check engine light and traction control light. The first time it happened I kept speeding up to see if it would come out of it and it did. Once past that speed range it hasn’t done it. The last time it happened, I was driving up a hill. Now that we’re home and not really any hills around here it won’t do it at all. Anybody have any issues with this?
 
#2 ·
Not with my Equinox yet (but I’ve still got the original factory plugs in mine ... so it’s coming) ... but I had it happen with my ‘97 Taurus twice! Both times I just replaced the offending plug and I was good for about a year each time. Turned out to be a gasket leaking coolant into that cylinder, fouling the plug.

I doubt that’s your problem, though - not enough miles, and no history of that with your engine. Maybe just try replacing that plug and see what happens?

BTW - 30+ years, almost 1 million miles driven, and I’ve yet to replace a single fuel injector! I think they’re built to be incredibly reliable.
 
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#3 ·
reading his description- Im thinking carbon buildup/sticky valves.
Though normally this would happen on a cold engine....
Have you run Techron Concentrate Plus?
 
#4 ·
I have not ran any cleaner through fuel system. The injector was diagnosed and replaced under gm warranty 47,000 miles ago. Also the current misfire code is only p0300 not a specific cylinder. I have read on here about similar issues but appears no one has figured out their problem.
 
#5 ·
I would start running techron.
Make sure its not the fuel injector cleaner.
You want to buy Chevron Techron CONCENTRATE PLUS.
it has a higher concentration of Techron- vs the Techron Fuel injector cleaner.
I would also buy the larger bottle.

I recommmend Techron, because GM uses this product when theyre doing repairs for carbon buildup in one of their service bulletins (its sold in their own bottle which says GM on it- but it looks just like the Techron bottle)
 
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