2007 Tahoe/Issues - engine light

Caligirl

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Background- My 2007 Tahoe has been running fine since I purchased about 10 months ago (at about 96k now)- hubby is keeping up on oil changes and he said not losing any and looks very clean (also had AFM "removed" via PCM), and still very low mileage daily driver with a few day trips. No towing.

Past couple of weeks it has intermittently been running a little rough at stops/idle and acting like its thinking of stalling, and there seems to be a little bit of hesitation an/or slight lurching when I accelerate from a stop.

While in park this morning after driving my big 6 mile commute, I pushed down on the gas pedal with window down and the engine sounds a little higher in pitch than normal, if that makes any sense- not quite as throaty. When I drive home today I'll see what kind of power it has going up the hill on the highway- it's quite steep and usually I can jump on it if i need to and it has no problem getting up the hill.

It has been getting down to the twenties at night, but I've also noticed it's been happening after the vehicle has been driven for a couple hours.

Never had anything show up on dash besides tire pressure or low gas alerts.

Question- if I'm having a misfire or some other issue, how bad will it get before I get a code, or is it possible to have issues like this and get no codes? (Like maybe codes aren't functioning???)

Husband can do basic repairs and maintenance but he does not have any diagnostic equipment, so no way for us to independently check for codes.

I know it's an older vehicle and with age will need repairs. But I don't want to jump at every little hiccup, but also don't want to ignore or wait for it to just clear up because I'm not getting any codes.

Thanks!

Edit- Started up the vehicle after work and solid engine light came on and running really rough. Don't fully understand this vehicle yet...will any other information come up or will it just be an engine light?
 
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Geotrash

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Background- My 2007 Tahoe has been running fine since I purchased about 10 months ago (at about 96k now)- hubby is keeping up on oil changes and he said not losing any and looks very clean (also had AFM "removed" via PCM), and still very low mileage daily driver with a few day trips. No towing.

Past couple of weeks it has intermittently been running a little rough at stops/idle and acting like its thinking of stalling, and there seems to be a little bit of hesitation an/or slight lurching when I accelerate from a stop.

While in park this morning after driving my big 6 mile commute, I pushed down on the gas pedal with window down and the engine sounds a little higher in pitch than normal, if that makes any sense- not quite as throaty. When I drive home today I'll see what kind of power it has going up the hill on the highway- it's quite steep and usually I can jump on it if i need to and it has no problem getting up the hill.

It has been getting down to the twenties at night, but I've also noticed it's been happening after the vehicle has been driven for a couple hours.

Never had anything show up on dash besides tire pressure or low gas alerts.

Question- if I'm having a misfire or some other issue, how bad will it get before I get a code, or is it possible to have issues like this and get no codes? (Like maybe codes aren't functioning???)

Husband can do basic repairs and maintenance but he does not have any diagnostic equipment, so no way for us to independently check for codes.

I know it's an older vehicle and with age will need repairs. But I don't want to jump at every little hiccup, but also don't want to ignore or wait for it to just clear up because I'm not getting any codes.

Thanks!

Edit- Started up the vehicle after work and solid engine light came on and running really rough. Don't fully understand this vehicle yet...will any other information come up or will it just be an engine light?
Glad you're enjoying your Tahoe!

That engine light will help you. Need a good scanner (preferably a Tech2) if you're going to have one of these trucks because you can get access to pending and stored codes, and sensor data that hold clues, but are not enough to trigger a check engine light. But now that you have a check engine light on, you can use almost any OBD2 scanner to get the basic codes triggering it. Time to go to Autozone or anywhere that can read the codes for you, for free. Then if you come back here with what you find, we can help you more.
 
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Caligirl

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Thanks! Husband is borrowing one from his boss. Going to come check it out and if nothing major, going to switch vehicles and he will limp it home.

I'm a Newbie with the "newer" Tahoes (owned 4 older Suburbans in past that didn't have any bells and whistles and they weren't fussy at all!) After reading so many posts on this forum, thought the Tahoe would give me a code itself haha. Didn't realize I needed another tool. Think I'll go on Amazon and procur one :)
 
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Caligirl

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Reading multiple P0300. Says random misfire... sigh...his mechanic friend says sounds like possible cam shaft??? (Based on the fact that the misfire seems to subside on higher RPMs)
 
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Caligirl

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That is the worse case scenario, of course, but his buddy wants to do a vacuum test first.

And it doesn't have any codes specifying any cylinder. From what I understand, random misfires are actually kinda hard to track down...
 
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Doubeleive

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do plugs n wires first and put some injector cleaner in it for a few tank fulls. at 94k it's time for plugs & wires anyway. also time for all 4 02 sensors
 
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Caligirl

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Brand new plugs n wires at its 85k service (sellers did a very thorough service, probably more than required, before we bought-$2300 at a dealer). It's at about 92k and I don't run it hard.
 

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A decent scanner will let you view the misfire count on each cylinder, and that might help narrow it down.
 
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