07 Tahoe: Service Stabilitrak & P0306 Code

[duhdude]

Hello all!

Ok, so I have an 07 Tahoe that has been running great. About two weeks ago the heater hose ruptured and sprayed coolant all over the engine....replaced, no issue.

Yesterday I was driving and all of a sudden the Service Stabilitrak/ABS light came on as well as the Check Engine light started flashing...the Tahoe started running and idling like complete dirt. -- Hooked it up to a code reader and it was a P0306 code.

So I have been needing to change the plugs and wires anyway...did a complete plug and wire job. Reset the code...same issue...same code. Trying to diagnose a bit further, I switched coil packs from the opposite side...same issue and code. Still running like dirt. There is NO coolant in the oil nor under the cap. Oil smells and looks great.

Today, I pulled the plug from cylinder #6 and it smells like strong gas and has gas soaked on it.

Thoughts?? I wouldn't think this would be a head gasket issue because of the oil and clean coolant, but could this possibly be a bad fuel injector or collapsed lifter?

(With he lifter, it's still quite on the passenger side so IMO it's not consistent with that as the ones I've heard are loud when collapsed).

Not sure where to proceed from here.

THANKS!

 

[Doubeleive]

maybe try a leak down test, that may tell you if it's the injector or not

 

[89Suburban]

Did you overheat it when the hose blew?

Swap that #6 coil with another one and see if it still fuel soaks that cylinder or not.

 

[wjburken]

Might be worth doing an inspection of the wire harnesses going to the injector and the coils just to rule those out as an issue.

 

[Fless]

Test for spark at that cylinder. Spark tester, and/or pull the plug, ground the threads, and make sure that plug is working.

 

[89Suburban]

I keep one of these in my tool box.

Amazon.com: Lisle 50850 Ignition Spark Tester : Automotive

Buy Lisle 50850 Ignition Spark Tester: Ignition Testers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[duhdude]

Might be worth doing an inspection of the wire harnesses going to the injector and the coils just to rule those out as an issue.

Funny you mention this, I went out just a bit ago to start working on this again and wanted to clear the codes before I did the leak down test (thanks Doubeleive for that!) and ever since the problem started it's only been code P0306...well this morning I have P0306 AND now P0356, which relates to a circuit issue on coil #6. When the heater hose ruptured, harness connection at #6 was soaked...So I'm now going to check the wiring harness and such and will report back. Thanks all for the suggestions.

 

[Geotrash]

Funny you mention this, I went out just a bit ago to start working on this again and wanted to clear the codes before I did the leak down test (thanks Doubeleive for that!) and ever since the problem started it's only been code P0306...well this morning I have P0306 AND now P0356, which relates to a circuit issue on coil #6. When the heater hose ruptured, harness connection at #6 was soaked...So I'm now going to check the wiring harness and such and will report back. Thanks all for the suggestions.

Sounds like you found your smoking gun. I find that WD-40 specialist electrical cleaner works well for that sort of task.

 

[Stubby1000]

@duhdude not sure if you already fixed the issue, but I recommend checking your ground strap on the back firewall. These Chevy vehicles have a metal braided strap that connects to the back firewall and the other side connects to the back of the valve cover on drivers side. When you sprayed coolant all over, it may have sprayed all over the ground strap which shorts out the system and causes the service stabilitrax warning. Remove this strap from the back of the valve cover with a 15mm wrench and you can clean it and re-install. Try that and see how it goes.