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2002 gmc envoy_slt
303 Posts
Discussion Starter #1
So I have a 2007 TB with about 113k miles, it has the I6 engine. I am very familiar with these engines as in the past I already have had an Envoy for many years and put over 175k miles on it.

A few months a ago I started to get the cylinder 4 misfire code and I read about every forum on here discussing it. I wanted it fixed so I bought a new plug and coil and put it in #4. I inspected the cylinder and it was dry and nothing abnormal. Also, I replaced all of the plugs with OEM ones just before 100k miles, so the are still fairly new.

I continued to get the code, granted it only happens every 1.5 - 2 weeks and it only happens when the engine is idling.

I did a compression test and the numbers seemed good to me. If I remember correct, somewhere in the 135psi range.

So at this point I was determined to get this fixed, so I had the fuel injectors professionally cleaned. Engine was running really smooth, guess what the code has come back????

At this point I am lost, I would really like to figure this out before taking it to the dealer.

If this helps a few times we have seen the random misfire code, but cylinder 4 seems to happen ~75% of the time.
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