Stabilitrak issue my journey so far.

[Taheezy_88]

Two weeks ago after placing 22inch rims with 33 inch tires I have been dealing with this issue. Engine code to begin with was P0621

First part I thought it was due to the new wheels and tires setting off the stabilitrak sensor. Ive resetted my abs system countless times and even today attempted again to just see if it work it didnt. When the "stabilitrak" first started I was getting "low engine power service engine" error on my dash so I followed the repairs.

Second part Full Tune up. I replaced Throttle body, MAF sensor, Plug wires, NGK iridium plugs, Alternator, belts just cause. (coil packs are on the list but see problems later) One fix seem to lead to another with the "stabilitrak" coming and going between each repair.

Third part Today driving after the second day of my tune up I felt i solved everything Truck was running strong. Later on in the day driving on the freeway I see the dam STABILITRAK Service tire system? but this time NO ENGINE LIGHT. I pull over unplug my battery try to restart cpu. Nothing works, I drove the care home slowly through back roads about 4 miles(i live in rural CA) When I get home I just said heck with it and Ibought a 350$ obd2 scanner.

4th part last diagnosis before this post. OBD2 determines a misfire in cylinder 4, I have an incredible knock in the engine now even louder with rev up. I am completely determined my lifters are done and top end rebuild is now in place.

I hope this post can shed some light to this problem and see that this error can lead to multiple different problems rather plugs, to who know what my problem is yet.

My question is anyone know of some good top end rebuild parts, performance based, forums where it has been done, parts list, etc..?

Guess my question is If im going to rebuild this I want to have a performance rebuild and any recommendations are welcomed thank you and sorry for the grammar.

 

[Taheezy_88]

.

 

[wjburken]

Welcome to the forum from Iowa.

Sorry to hear about your issues.

There are a number of folks here that have gone down the path you are on. @iamdub has a good build thread that documents his AFM delete rebuild. There are others, but I am drawing a blank at the moment.

Might share a little more about your vehicle like year, motor, miles, other upgrades or work done, etc. What do you consider a performance build?

Would also be helpful if you shared more about the codes you were getting as you may have other things going on as well. I can’t say I’m familiar with the P0621 DTC code.

 

[Taheezy_88]

Welcome to the forum from Iowa.

Sorry to hear about your issues.

There are a number of folks here that have gone down the path you are on. @iamdub has a good build thread that documents his AFM delete rebuild. There are others, but I am drawing a blank at the moment.

Might share a little more about your vehicle like year, motor, miles, other upgrades or work done, etc. What do you consider a performance build?

Would also be helpful if you shared more about the codes you were getting as you may have other things going on as well. I can’t say I’m familiar with the P0621 DTC code.

Hey thank you for the response.
Current is 2007 tahoe 5.3l LT 4wd
No mods except aftermarket Carven exhaust
22 inch wheels 33inch tires can get the tire spec tomorrow
I run aggressive as you can tell by my looks and anything performance wise that adds HP and of course quality is what I want. This is my work/family truck so I'm willing to go the extra mile on parts for it just looking for the right direction. Mechanically I'm handy done some rebuilds and always maintain my own.
Miles 147k always maintained
P0621 only code I've been throwing and low oil pressure from time to time.

 

[Taheezy_88]

How do I tell if my 5.3 is vvt or non vvt? Is 2010+ a good standard for vvt engines and any year below is non vvt?

 

[wsteele]

How do I tell if my 5.3 is vvt or non vvt? Is 2010+ a good standard for vvt engines and any year below is non vvt?

2010 on for VVT on your model.

Here is a link for the DTC, https://www.obd-codes.com/p0621

Before pulling the heads, I would pull a valve cover and make sure you actually did have a dead lifter on number 4. You very easily could have gotten a bad plug/wire, etc. with all your parts replacing.

Good luck.

 

[iamdub]

Throwing a ton of parts at it semi-aimlessly can bury the problem deeper rather than fix it and it can cause other problems. Just because a part is new doesn't mean it's "good". This is especially true with cheap aftermarket electronics (sensors, plug wires, etc.).

First off, we need to clarify the events and when they happened. This is the timeline I'm understanding from your post:

1) All was well and you installed new wheels and tires

2) Soon after, got a P0621 (I'm showing that to be for a fault in the charging circuit light, as in a dead bulb in the cluster)

3) Tahoe started going into "Limp Mode" (Service Stabilitrak and Reduced Engine Power)

4) You replaced a bunch of tune-up-related parts and found no stable improvement

5) It ran fine for a couple of days then the Stabilitrak message popped up again

6) You bought a scanner and found #4 misfire and then noticed a "knock"


^^^ Is this accurate?

First thing I'd do is double-check my work. Were the plugs gapped properly? Make sure the spark plug wires are fully locked in. While you have your hands on them, do a quick test by swapping the #4 wire with one from the opposite bank and see if the misfire follows or goes away entirely.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

You are already receiving responses to your inquiry, and other folks will chime in.

 

[Doubeleive]

for that p0621 you may want to double check your connections on the alternator and battery and/or the replacement alternator could be defective
this guy goes real deep into it, but the end result was a bad alternator

 

[Taheezy_88]

Yes timeline is correct. Thanks for the response. I have installed these parts over a two week timeline only replacing one to replace another. I got most of that advice from here TB, Plugs, Wires, MAF, Alternator, etc. One part to another.I'll check my plug on #4 and pull the cover.