2006 tahoe misfire at idle and noise at idle

[Dustyhd05]

2006 tahoe with misfire on 2 and 7 only at idle and goes away when accelerating, loud rattling noise when at idle and accelerating. I have a video of the noise how do I post that

 

[Dustyhd05]

 

[strutaeng]

It's not your catalytic converter?

 

[Dustyhd05]

It's not your catalytic converter?

will that cause the misfire at idle and not when driving?

 

[strutaeng]

will that cause the misfire at idle and not when driving?

A misfire if driven for a long time will damage catalytic converters. If the check engine light blinks, that's basically telling you that catalytic converters are getting damaged.

So the misfire is the underlying problem. Cat damage is the result of that.

First thing to diagnose is the misfire. Pull plugs, swap coil packs and see if misfire changes cylinder, check plug wires, injector balance test or swap, etc. If everything looks good, mechanical check will be next: compression test and leak-down test.

 

[Fless]

Cracked flexplate? Loose exhaust shield?

 

[Dustyhd05]

A misfire if driven for a long time will damage catalytic converters. If the check engine light blinks, that's basically telling you that catalytic converters are getting damaged.

So the misfire is the underlying problem. Cat damage is the result of that.

First thing to diagnose is the misfire. Pull plugs, swap coil packs and see if misfire changes cylinder, check plug wires, injector balance test or swap, etc. If everything looks good, mechanical check will be next: compression test and leak-down test.

I replaced all plugs and coils and wires and swapped after repair and nothing changed. Check compression test forgot the numbers will do again soon and do remember cylinder to be all pretty close.

 

[Dustyhd05]

Cracked flexplate? Loose exhaust shield?

Cracked flex plate can I do something to check that or do I have to pull trans to check that? I check shields and nothing loose thanks

 

[Fless]

You can use the transmission inspection port and a endoscope camera; with that you might be able to see any cracks.

 

[Dustyhd05]

You can use the transmission inspection port and a endoscope camera; with that you might be able to see any cracks.

Thanks I’ll try that

 

[nonickatall]

I would remove the valve covers to check if there a loose rocker arms, which can show a failed hydro lifter.

A clogged cat can cause misfire, because the engine can not get rid of the exhaust gas which leads into bad firing.

I would also exchange ignition coils, to check if the error alternate as well. Also you can do that with injectiors

 

[Dustyhd05]

I would remove the valve covers to check if there a loose rocker arms, which can show a failed hydro lifter.

A clogged cat can cause misfire, because the engine can not get rid of the exhaust gas which leads into bad firing.

I would also exchange ignition coils, to check if the error alternate as well. Also you can do that with injectiors

Thanks for the ideas. I’m going to removed the rockers on number 7 and check and see if the lifters and cam is jacked because it is a hard miss on 7 and 2. I have swapped coils and injectors already and doesn’t move.

 

[nonickatall]

You don't need to remove them, just check if they feel loose and have play.

 

[555hp]

Thanks for the ideas. I’m going to removed the rockers on number 7 and check and see if the lifters and cam is jacked because it is a hard miss on 7 and 2. I have swapped coils and injectors already and

 

[nonickatall]

You don't need to remove them, just check if they feel loose and have play.

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