08 Tahoe help!! Cylinder #1 misfire

[Isaiah13]

I have a 08 Tahoe with 157k miles on it. The engine light came on, I had it scanned and it showed cylinder #1 misfire. I just replaced all the plugs and wires about 2 months ago, so I thought maybe it was the coil, I took the coil off cylinder #1 and swapped it with #3 coil to see if the actual coil was bad. The engine light went off and was fine until I drove home from work today and it came back on. Scanned it and reads cylinder miss fire #1, so it’s not
The coil I don’t think.
The Tahoe is running good other than a slight miss when idling but nothing real noticeable and the rpm hand is bouncing up and down slightly at idle. I haven’t tired replacing the injector yet, and I haven’t done a compression test on #1 cylinder yet. I know it could be multiple things like a stuck lifter and what not . I was just wondering if anyone has
had this problem and could point me in the right direction. Thanks!

 

[OR VietVet]

Start with a compression and compare #1 and #3. Check for vacuum leaks. You said you replaced plugs and wires, did you pull the plug to inspect? Did you check to be sure the plug wire is "snapped on" correctly?

 

[Isaiah13]

I haven’t pulled the plug to inspect it yet, the plug wire is snapped on correctly. I’m going to start checking everything over really well tomorrow. Hoping for a simple fix.

 

[Fless]

In addition to @PNW VietVet's suggestions, watch for a bad plug wire, plug gap, carbon tracking on the plug insulator, etc. Swap one thing at a time with another cylinder and see if the problem follows.

 

[George B]

First thing I would do is swap that plug to a different cylinder. Always go back to the recent work and check before assuming it’s good. Parts can be bad out of the box.

 

[easymoney]

I have a 08 Tahoe with 157k miles on it. The engine light came on, I had it scanned and it showed cylinder #1 misfire. I just replaced all the plugs and wires about 2 months ago, so I thought maybe it was the coil, I took the coil off cylinder #1 and swapped it with #3 coil to see if the actual coil was bad. The engine light went off and was fine until I drove home from work today and it came back on. Scanned it and reads cylinder miss fire #1, so it’s not
The coil I don’t think.
The Tahoe is running good other than a slight miss when idling but nothing real noticeable and the rpm hand is bouncing up and down slightly at idle. I haven’t tired replacing the injector yet, and I haven’t done a compression test on #1 cylinder yet. I know it could be multiple things like a stuck lifter and what not . I was just wondering if anyone has
had this problem and could point me in the right direction. Thanks!

I would replace that plug to start with. Its cheap. Just because you put a new plug in there doesnt mean its not defective. If you have the old wire maybe put that wire back on at some point if you continue to have issues

 

[madmanjustice]

i had the same thing on my PPV. I swapped the 1 and 3 coils and still had the misfire on number 1. So i swapped the plugs and wires on 1 and 3 and the misfire moved to number 3. I went ahead and replaced all the plugs and wires and cured the misfire until I totaled the PPV.

 

[RED TAHOE LS]

I have a 08 Tahoe with 157k miles on it. The engine light came on, I had it scanned and it showed cylinder #1 misfire. I just replaced all the plugs and wires about 2 months ago, so I thought maybe it was the coil, I took the coil off cylinder #1 and swapped it with #3 coil to see if the actual coil was bad. The engine light went off and was fine until I drove home from work today and it came back on. Scanned it and reads cylinder miss fire #1, so it’s not
The coil I don’t think.
The Tahoe is running good other than a slight miss when idling but nothing real noticeable and the rpm hand is bouncing up and down slightly at idle. I haven’t tired replacing the injector yet, and I haven’t done a compression test on #1 cylinder yet. I know it could be multiple things like a stuck lifter and what not . I was just wondering if anyone has
had this problem and could point me in the right direction. Thanks!

Take one of your wires and exchange # 1 plug wire

 

[Isaiah13]

I appreciate it, I will try to swapping the plug and plug wire and see if misfire follows.

 

[George B]

Don’t move two parts. Only move the plug or only move the wire. Otherwise you will still need to determine if it’s the plug or wire. Make one change at a time.

 

[Isaiah13]

I checked today to make sure I didn’t have a stuck lifter, checked compression it was all good. The #1 plug was the problem. Replaced it running fine now, engine light gone.

 

[wsteele]

View attachment 350356I checked today to make sure I didn’t have a stuck lifter, checked compression it was all good. The #1 plug was the problem. Replaced it running fine now, engine light gone.

Looks to be a tad more than .040"

 

[Fless]

Looks like more than 2 months' worth of wear on that new plug. Are you running platinum plugs, or iridium?

 

[OR VietVet]

Looks like more than 2 months' worth of wear on that new plug. Are you running platinum plugs, or iridium?

Exactly what I was gonna say. Something is going on in that cylinder. I also agree with @wsteele about the plug gap and would be curious what plugs you used.

Compression readings and comparison with cylinder #3?

Should be this plug: https://www.rockauto.com/en/moreinfo.php?pk=10351600&cc=1441040&pt=7212&jsn=911

 

[Fless]

You may have had some carbon tracking where I've circled in red:

 

[Isaiah13]

they are iridium plugs.

 

[OR VietVet]

they are iridium plugs.

Whose Iridium plugs?

 

[Fless]

Whose Iridium plugs?

And where were they purchased?

 

[Isaiah13]

Advance auto

 

[OR VietVet]

I guess I will ask just one more time, whose makes the plugs? Also, while I am at it, whose makes the plug wires? Compression readings compared between #1 and #3?

I promise, last time I ask these questions and then I just give up and will stop bothering you.