2017 Tahoe Headers and Exhaust Questions/Trades

[Chris Harris]

I have a 2017 Tahoe Premier that has 26,000 miles on it. Bought it used at around 15,000 miles on it. It came with aftermarket headers and exhaust system. I know the exhaust is Flowmaster but don't know anything else about it. The dealership removed the cold air intake and sold it without. I didn't know any better nor did they.

I have been driving it for the past 6 months and get this rattling sound that comes from under my feet when I put a load system like being in a low gear or going up a hill. I can only guess this is coming from not enough air flow and the manifold is vibrating off the cross beam under heavy load. I have also had some On Star Codes show up for emissions system issues during this time. My guess is it is becoming too gas rich without the proper airflow.

Fast forward to yesterday, my car won't accelerate past 35 miles per hour. I get the followong On Star Diagnostic codes: Engine and Transmission System, Antilock Braking System, Stabilitrak System, and then my front impact sensor says it is not functioning as well.

I'm about to revert back to stock and pull this system off and will practically give it away if this is the root of my problems.

Looking for help and advice!

 

[Tahoe14]

I would go back to stock, no telling how much it is going to cost to trouble shoot or fix the issue if it can even be fixed. Just my .02 worth.

 

[avalonandl]

Before you do anything get the codes read. I assume the Check engine light is on. I doubt the headers are the problem. It sounds like a plugged catalytic converter or your exhaust system is plugged somehow.

 

[Thrust]

Make sure one of the O2 sensors isn't grounding. Sometimes on aftermarket exhaust the O2 bung is not in the right place. Make sure it isn't contacting the body.

 

[gat0r]

what avalonandl said


& it could also be loose header Ypipe connector too.

given what you mentioned, my first thought would be clogged cat too

 

[Chris Harris]

My mechanic is saying there are throttle body codes as well and none of those issues should cause throttle body codes. He said there are about 15 codes on the car.

 

[iamdub]

My mechanic is saying there are throttle body codes as well and none of those issues should cause throttle body codes. He said there are about 15 codes on the car.

But a faulty throttle body or its wiring circuits could cause those. At least on the previous two generations and more so on the older ('00-'06) ones, the harness to the TB was a common failure point- bad pins in the plug or something. It's so common that there's a replacement plug with a pigtail harness. You cut off the old one and splice on the new one.

I'd clear the codes and look to see if any of those circuits fail the check at KOEO. Might have to move the wiring around.

Live in a salty area? Corroded grounds can wreak havoc on the electrical system, causing all sorts of issues in otherwise unrelated systems. A failing battery with a shorting cell or faulty alternator sending voltage spikes could do the same.

 

[fozzi58]

I have a 17 Burb with CAI and exhaust mods and without a tune the truck will not know the different between factory manifolds, Kooks headers, Flowmaster, Borla, whomever exhaust was installed.

I would agree - clogged cat. Possibly wiring issue.

Installing headers (or cold air intake) will not cause your truck to not accelerate or throw codes unless improperly installed. And without changing the tune of the truck - headers, exhaust, intake will not cause enough of a change that the computer can't adjust your fuel/air ratio for your truck not to run. Swapping out your headers and flowmasters for factory components is a waste of money and will not fix the root of the issue.

 

[Chris Harris]

Evidently I need to take it to the dealership and have them reprogram the ECM with the latest software. Getting a DTC P2101 code which causes the electronic throttle control issue.

Hoping this fixes the issue.

 

[Staggered 02]

Sort of makes sense. Hopefully that in fact resolves your issue. I too am in the clogged cats (if you have them) and wiring issue if the ECM iupdate does not work. Where do you live? Some states are not as sensitive to emissions. And some vehicles are off road use only which would allow for an exhaust with no cats.

Relevance there is if you had no cats you would not hav a cat issue to contend with regardless. Headers are not going to give you those type of performance or code problems if everything is installed correctly (i.e. O2 sensors, wires not grounding etc).

I am running headers on almost all of my vehicles. No issues. The Duramax is on deck for performance upgrades. I am so ready.

Good luck with your troubleshooting. Hang in there.