Tonyrodz's Tahoe Build Thread

[Fless]

Went to my mother's for Christmas today and took the Hoe. She lives on a really quiet street--and it is loud. We were talking and she said she heard what sounded like a miss--kind of--as I was driving down the street. I was going less then 10 miles an hr. I knew I was hearing what sounded like popping from the exhaust when I drive--I can also feel it in the truck. I knew I wasn't imagining it, since my mother confirmed hearing it too.
Funny--when in park I can rev the hell out of it and it sounds fine, only happens when I'm driving. Doesn't matter if I'm on the highway or local streets, same thing.

A mother with good hearing -- scary! But maybe she can troubleshoot the miss? LOL

 

[Tonyrodz]

A mother with good hearing -- scary! But maybe she can troubleshoot the miss? LOL

I wish!

 

[Tonyrodz]

I used to have a 02 F150 with the 5.4 and it would do something similar to what you're describing. It ended up being a weak coil. I know our LS engines don't typically have coil issues, but maybe you have a weak one that isn't bad enough to set any codes yet.

It's def something and it's driving me crazy trying to figure it out. Thx for the idea tho. What's a good way to check a coil?

 

[Fless]

I may have missed it, but have you been able to monitor live data for the misfires on each cylinder? To see if that's what it is?

 

[Tonyrodz]

I may have missed it, but have you been able to monitor live data for the misfires on each cylinder? To see if that's what it is?

Actually I had the tech 2 to monitor misfires--got 0 misfires in all cylinders, but that was while in park--which it idles fine. I haven't done it while driving.

 

[Rocket Man]

Hook up your Tech2 and look at misfires, leave it connected while you drive around and then check history. It can point you to a cylinder or 2 and then you can switch things around ( plug wire, coil, plug, etc) one item at a time and see if the misfires follow. It could be as simple as a plug wire or injector harness, or coil, etc. On my Denali I could feel it run rough under boost only and using the Tech2 I was able to find a plug wire that had burned inside the header boot that was supposed to keep them from burning. It was just discolored but must have affected the insulator inside the wire enough to cause misfires under load.

 

[Tonyrodz]

Hook up your Tech2 and look at misfires, leave it connected while you drive around and then check history. It can point you to a cylinder or 2 and then you can switch things around ( plug wire, coil, plug, etc) one item at a time and see if the misfires follow. It could be as simple as a plug wire or injector harness, or coil, etc. On my Denali I could feel it run rough under boost only and using the Tech2 I was able to find a plug wire that had burned inside the header boot that was supposed to keep them from burning. It was just discolored but must have affected the insulator inside the wire enough to cause misfires under load.

I def will do that. Thx Mark.

 

[Bigkevschopshop]

Kinda sounds like lean surge, or timing a bit off some something else.

I know that if your too lean at cruise under load it will slightly buck and make some coughing out of the exhaust. Lean misfire, depending on your tune the pcm may not pick it up. Pull the plugs yet?

You may look at the coolant temp sensor, sometimes a parameter off will cause things to go haywire. And only reason I go there is the issue is more prevalent at warmed up conditions.

Do you feel it buck at all or is it all in exhaust?????
If not, check for a header leak or exhaust leak somewhere, sucking air may be re igniting and causing things.... I know it sounds weird but Ive seen a car that ran perfect, no miss, full tune up, start popping out the exhaust, the shop tore the car down expecting the worse.... Turned out to be a cracked header at a weld, sucking in a small amount of air causing a reburn in the exhaust...

Also timing curve, if your timing curve was screwed with and its retarded for what it really wants at an rpm, it will do this junk also man...

I know its not helping but just throwing shit out there.....

 

[Tonyrodz]

Kinda sounds like lean surge, or timing a bit off some something else.

I know that if your too lean at cruise under load it will slightly buck and make some coughing out of the exhaust. Lean misfire, depending on your tune the pcm may not pick it up. Pull the plugs yet?

You may look at the coolant temp sensor, sometimes a parameter off will cause things to go haywire. And only reason I go there is the issue is more prevalent at warmed up conditions.

Do you feel it buck at all or is it all in exhaust?????
If not, check for a header leak or exhaust leak somewhere, sucking air may be re igniting and causing things.... I know it sounds weird but Ive seen a car that ran perfect, no miss, full tune up, start popping out the exhaust, the shop tore the car down expecting the worse.... Turned out to be a cracked header at a weld, sucking in a small amount of air causing a reburn in the exhaust...

Also timing curve, if your timing curve was screwed with and its retarded for what it really wants at an rpm, it will do this junk also man...

I know its not helping but just throwing shit out there.....

I would say it's more a chugging then a bucking. It was really noticeable driving up a hill, and when you keep steady pressure on the pedal. Honestly I haven't really done anything else since I did the alignment to it. Other things going on for me personally.
Not sure if it's my imagination but it seems like it takes just a little bit longer to warm up then it used to. Nothing crazy, and it might just be the thermostat. It doesn't take crazy long, but it just seems a tick longer. I'd think the tune would've stayed the same as before, since no one has even messed with that.
I plan on saving up for the BB tune. I know they'll be able to see if something wacky is going on. I'll have to pull the plugs too. That popping is really pissing me off. I haven't heard any exhaust leak under the hood, still sounds good under there--no ticking or other strange noises. Thx for the ideas, any and all suggestions are good.

 

[iamdub]

I'd really be moving the tune up the priority list. If you're running lean, it could be a ticking (or popping?) time bomb. One good WOT blast could be the last. A good tuner would be able to see how it's running and what may be causing the pop. Fixing the issue (tune, fuel pump, injectors... whatever) rather than repairing it's consequences if left alone would be much cheaper. Until you know what's goin on, drive it easy.

 

[Rocket Man]

I'd really be moving the tune up the priority list. If you're running lean, it could be a ticking (or popping?) time bomb. One good WOT blast could be the last. A good tuner would be able to see how it's running and what may be causing the pop. Fixing the issue (tune, fuel pump, injectors... whatever) rather than repairing it's consequences if left alone would be much cheaper. Until you know what's goin on, drive it easy.

Good advice right here, Tony.

 

[Tonyrodz]

I'd really be moving the tune up the priority list. If you're running lean, it could be a ticking (or popping?) time bomb. One good WOT blast could be the last. A good tuner would be able to see how it's running and what may be causing the pop. Fixing the issue (tune, fuel pump, injectors... whatever) rather than repairing it's consequences if left alone would be much cheaper. Until you know what's goin on, drive it easy.

Good advice right here, Tony.

Agreed. I have nailed it a few times in frustration.

 

[Tonyrodz]

I didn't take out number 8. So starting from the left this is 6 4 and 2.

I even the gaps to about .045. Some were a hair off, maybe .048. It looks like he might have used the old plugs. These plugs should still look brand new, Especially the one with the rust around it. Over all I don't think the tips look horrible. I will change them come spring. Definitely not causing an issue.

 

[Dantheman1540]

The tips don't look bad but dang the rust on that one your holding in the pic is awful. Keep pulling them I suspect one may be your issue.

 

[Tonyrodz]

1, 3 and 5. Looks pretty normal.

 

[Tonyrodz]

Gonna try to get #7 out.

 

[Rocket Man]

I didn't take out number 8. So starting from the left this is 6 4 and 2.View attachment 266274 View attachment 266275 View attachment 266276
I even the gaps to about .045. Some were a hair off, maybe .048. It looks like he might have used the old plugs. These plugs should still look brand new, Especially the one with the rust around it. Over all I don't think the tips look horrible. I will change them come spring. Definitely not causing an issue.

Shit replace them with some cheap copper ones instead of putting those back in, especially #8 because that one might be the problem. Coppers are only a couple bucks apiece, then come spring put the good ones in when you have the cash.

 

[Tonyrodz]

Shit replace them with some cheap copper ones instead of putting those back in, especially #8 because that one might be the problem. Coppers are only a couple bucks apiece, then come spring put the good ones in when you have the cash.

Too late for today. I will, but not today. I fought with that #8 plug and said F* it.

 

[Rocket Man]

Too late for today. I will, but not today. I fought with that #8 plug and said F* it.

That might be why it’s causing a problem, those might be the plugs that came in that engine and haven’t been changed for who knows how long. For #8 try this- your 5/8” plug socket can take a 3/4” regular socket on it, then your ratchet. Like this.

Then it’s the exact right length for #8. It’s so easy that way you won’t believe it. Try it.

 

[Tonyrodz]

Well, well. Lookey lookey--

This is #7. See anything wrong?
Plus it was gapped at .040