2007 Tahoe/Issues - engine light

[Caligirl]

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?

 

[Miami-Dade]

Moved and changed the title.

 

[Geotrash]

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.

 

[Caligirl]

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

 

[Caligirl]

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)

 

[CaptainAmerica1]

Collapsed afm lifter… break out the checkbook…

 

[Caligirl]

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...

 

[Doubeleive]

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

 

[Caligirl]

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.

 

[Fless]

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

 

[Caligirl]

Hmmm, we didn't have the instructions for the scanner we borrowed, so not sure how to find. Hopefully his buddy can narrow down.

 

[Fless]

Hmmm, we didn't have the instructions for the scanner we borrowed, so not sure how to find. Hopefully his buddy can narrow down.

Lots of manuals online, might try finding it there.

 

[Geotrash]

Hmmm, we didn't have the instructions for the scanner we borrowed, so not sure how to find. Hopefully his buddy can narrow down.

This is the one you need:

Cheap GM Tech2/ Saab Tech2 Diagnostic Scanner Full Package

GM TECH2 Scanner Full package comes with free TIS2000 Software, you can choose one kind of software for GM, SAAB, OPEL, SUZUKI, ISUZU, and Holden.

www.chinacardiags.com

 

[Joseph Garcia]

If you are going to buy a scanner, you would be best served by purchasing a Tech 2.

 

[Caligirl]

So troubleshooting showed no vacuum leaks or other obvious causes or major issues. He cleared the CE light and said to drive it for a few days and rescan. We are probably going to go ahead and change spark plugs and wires as a pretty inexpensive troubleshooting. Hope we aren't going to spend months tracking this down.

 

[Blkbrd21]

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?

Just purchase a code scanner from autozone and that should put you at ease, it may be your maf sensor (05 suburban),I hope this helps

 

[robhotdog]

Make sure the previous owner put it OE spark plugs!! Aftermarket Gee Wizz cause all kinds of ignition problems..always stick with factory ignition parts. 0300 can be caused by vacuum leaks. Run Chevron fuel injection cleaner thru it. Black bottles. If your not hearing abnormal ticking or squeaking at idle your valve train is ok. If I was going to replace anything at that age and milage it would be the injectors. Assuming new plugs and wires. Use only Factory replacement parts!!

 

[emamon]

I would not buy a Tech2 unless you have a time machine to go back to 2014 went they went obsolete. Note that you still have all of the AFM/DOD components from your OP. The disabling has just been overridden in software but you still have AFM lifters and camshaft. My gut tells me that a plug or coil wire would trigger a P0301-Po308 instead of P0300. If you hear a loud ticking on one bank of the engine I would remove that valve cover, disable the fuel pump relay/controller and observe valve operation while spinning the engine. This vid is good background if it is a collapsed lifter issue

 

[petethepug]

This is a little snarky but are you saying don’t use the $3k GM diagnostic tool available for $300 and gut check the truck? The only thing obsolete about the GM specific / Tech II scanner is it’s price.

There’s an unplanned part going obsolete on these trucks causing emission related codes. It’s the charcoal carbon canister. As your going through the diagnostic process make sure the items specific to the 50 & 100k mile maint intervals are replaced.

Like previously mentioned, the plugs, wires, T/B cleaning or a tank of e85 if compatible.

 

[Caligirl]

So update...hubby takes all his GM work vehicles to local dealer and managed to get my Tahoe scanned on the cheap. Was a cracked sparkplug (outer porcelain) and corroded wire. That's. All. And they did an inspection and washed it to boot Sparkplugs only had about 10k on them (iridium). Husband suspected installation issue maybe? He says purrs like a kitten. He also said that the mechanic has worked on 3rd generation a lot and the lifters on these do not fail as much as the NEW ones.