Truck seems to like 1st gear too much

Check the springs. Seriously.

Yup! I was right its a coil. Hooked it up to the modis at school today and cylinder 3 shows 4,600 misfires in the history.

And I might aswell change springs if Im going to have the intake off to change the knock sensors. I might as well change them and the harness now. Also, will doing the TB delete and the EGR delete gain much performance/economy?

In my experience the missfires you are speaking of will not end up being an ignition coil I am willing to bet you have burnt valves as others have said it could be a result of weak springs, as far as the pinging I am sure you are aware of the GM buletin which describes the cause and correction I can get it for you if you would like.

If it were an ignition coil the check engine light would flash at idle also as well as all the time, not to mention it would have over 46000 missfires current not to mention way too many history to count since a failed coil would almost certainly missfire every revolution.
The mass airflow sensor could cause the pinging and poor performance if it is contaminated which actually could lead to burnt valves from a resulting lean condition, which would also damage the cats.

FYI the check engine light flashes to inform the driver of a catalyst damaging missfire meaning you are either putting raw fuel into the cat or extremely high exaust gas temps are expected because of a lean condition.
Lastly I have seen trucks which have had missfires on one or more cylinders which was corrected by doing a crankshaft variation relearn.
If you wanna verify its the coil swap it with any other one and see if it the problem follows the coil.

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Originally Posted by decibles

In my experience the missfires you are speaking of will not end up being an ignition coil I am willing to bet you have burnt valves as others have said it could be a result of weak springs, as far as the pinging I am sure you are aware of the GM buletin which describes the cause and correction I can get it for you if you would like.

If it were an ignition coil the check engine light would flash at idle also as well as all the time, not to mention it would have over 46000 missfires current not to mention way too many history to count since a failed coil would almost certainly missfire every revolution.
The mass airflow sensor could cause the pinging and poor performance if it is contaminated which actually could lead to burnt valves from a resulting lean condition, which would also damage the cats.

FYI the check engine light flashes to inform the driver of a catalyst damaging missfire meaning you are either putting raw fuel into the cat or extremely high exaust gas temps are expected because of a lean condition.
Lastly I have seen trucks which have had missfires on one or more cylinders which was corrected by doing a crankshaft variation relearn.
If you wanna verify its the coil swap it with any other one and see if it the problem follows the coil.

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If you don't mind I would like to know the TSB for it. I don't know if the one about putting silicone around the knock sensors is the same one. Just a few hours ago I gutted the cats and WOOOOW!!!! :burnrub:There is no hesitation at all and is completely back to normal if not better. However, I can't hear if it is still pinging with the cutout open. I will see tomorrow with it closed but it really feels like a new truck, I am amazed. No flashing SES light anymore either, and it pulls hard in the upper rpm's like never before it seems. But I did just change to a trutrac and 4.10's so I may be feeling that lol. Also, I just recently cleaned the MAF, throttle body, changed plugs to TR6's and changed plug wires, and ran seafoam through it. Thanks for yours, and others input.

I will get back to you with the tsb number this afternoon, glad you got taken care of I definately believe the cat was causing your low revs but not a single cylinder missfire. I am willing to bet there is something else going on with number three missfiring even though it isn't doing it now it must be weaker than your other cylinders(leaking valves,weak springs,dirty injector, etc.). I hope I am incorrect it just doesn't make sense besides something caused the cats to fail, I have experienced a plugged cat causing spark knock when in that situation only one of the cats had actually failed the other was still good and it was a result of an injector which was leaking by on cylinder number 7.