05 Chevy Tahoe Z71 5.3L issues

Flexpipe · March 14, 2012, 01:16:21 AM

Need help with a few issues I am having with my 05 tahoe just replaced plugs and wires on it and shortly after check engine light blinks once in a while but its not misfiring at least its not noticeable it seems to be running damn good. The check engine light blinking usually means that it goes into limp home mode but i don't understand it.

I scanned the codes on it and it says cylinder 8 misfire but i checked all the plugs and wires and they are fine. the only thing i can think of is that the coil pack for that cylinder is going bad but not sure. I didn't replace those because they are $35 a piece and i figured if a coil pack goes bad its just bad but if anyone knows anything about this it would help me out thanks. It has had a bad 02 sensor for a while so the check engine light has been on for that but I don't think that would have anything to do with this.

If anyone could help on here

The second issue I'm having is my tachometer stopped working on me it works sometimes but most of the time its stuck all the way up. If anyone knows how to fix this or if that is an electrical issue with my instrument cluster. This truck only has 95000 miles on it.

ToughBowtieTruck · March 14, 2012, 01:23:07 AM

Steady light is a stored code. Not necessarily meaning in "limp mode" anymore with these new vehicles, as it could be a misfire, emission code, etc.

Flashing light means engine misfire is happening. If it is flashing the engine is misfiring. Try swapping #8 coil with another cylinder's to see if the misfire jumps cylinders. If it does, it's the coil.

As for the tach, I know a LOT of late model GMs have trouble with the clusters going out. Yours is probably in the cluster.

xjs3667 · March 14, 2012, 01:25:36 AM

what Spark plugs did you use, If not ac-delco they can give you a miss fire code, I doubt that its a coil pack, also check to make sure the plug wire is clicked onto plug and the metal heat shield is pushed all the way down, they lock the wire down on the plug.

also as for the tach, I believe Gm has a voluntary recall out for that gauge cluster as the speedometer also does that. call a dealer near you and they can tell ya

also flashing light means something wrong with emissions, IE: o2 sensor, or plugged cat something along those lines, usually will trip when 2 or more o2 sensors go out

Flexpipe · March 14, 2012, 01:34:39 AM

the plugs are not Ac-delco but they are bosch iridium plugs so i know they are correct plugs and i checked all that. just cant figure out why number 8 is saying misfire But I am going to try switching coils to see if my coil is bad.

xjs3667 · March 14, 2012, 01:46:52 AM

Quote from: Flexpipe on March 14, 2012, 01:34:39 AM
the plugs are not Ac-delco but they are bosch iridium plugs so i know they are correct plugs and i checked all that. just cant figure out why number 8 is saying misfire But I am going to try switching coils to see if my coil is bad.

Ive never had any luck with any bosch plugs....lol...but thats just me..... but if its not the coil re-check plug wire on #8 again and again lol #8 is the hardest one to change on them and might be still not correct...... It took me 3 days of fiddiling with that one to finally get it, and it was just that the wire didnt clip on the plug even tho it felt like it every 100X that I checked it but then it took that one time of me just getting real mad and then it clicked and that made me even more mad lol

good luck hope you can find your problem

Flexpipe · March 14, 2012, 01:50:12 AM

Yeah i know that one is the worst one I'll keep checking it cuz its pissing me off that i cant figure it out

ToughBowtieTruck · March 14, 2012, 02:31:03 AM

The owner's manual tells of the check engine light and how it flashes to show a misfire. It flashes as a current warning to stop running the truck if the misfire continues because the misfire can cause engine damage.

I have a random misfire code on my Silverado that flashes the CEL that happens at exactly 57mph in Tow/Haul that I cannot figure out myself. Also get a steady CEL from a "cat conv efficiency below threshold bank 1" at random times.

Doubtful it's a coil, but if it were the plugs, I would suspect the other cylinders would act up as well. Which would lead me to side with xj's suggestion of the plug wire.

Eroq · March 14, 2012, 03:06:33 AM

flashing check engine light is a catalyst damaging misfire, take care of it before you do more damage.. did it misfire before you did the tune up? what brand are the wires? ive had brand new wires right outta the box... swap out the wires, use AC delco plugs.

make sure wires are seated all the way, lotta little things will make a difference, if you luck you might have a bad injector on #8 need a good scanner to watch the pulse width. hook up fuel pressure gauge, command the #8 injector to open and observe the fuel pressure drop... many more things you could do but id start with the stuf you've already replaced...

Strapless · March 15, 2012, 04:47:07 AM

I know specmo in flint will redo the cluster. i dont remember the price but very common.

Jr · March 15, 2012, 04:57:54 AM

pull them junk ass bosch plugs out.. go get you an platnum delco plug...

i dont even run them

bosches in my push mower! they are garbage.

72 Bogger · March 15, 2012, 03:41:56 PM

Everybody else is giving you good sugjestions on the missfire. As for the tach mine on my 98 chevy started acting up and finaly stoped working and I was told it was probably the cluster also but that wasn't it. I had some other isues of it not starting so I was going threw the wiring to find out why and as I was doing this I noticed ohe of the three wires that are on the plug for the coil was broke fixed that and my tach started to work again. So I would check those wires. Good luck

xjs3667 · March 15, 2012, 07:43:39 PM

Quote from: 72 Bogger on March 15, 2012, 03:41:56 PM
Everybody else is giving you good sugjestions on the missfire. As for the tach mine on my 98 chevy started acting up and finaly stoped working and I was told it was probably the cluster also but that wasn't it. I had some other isues of it not starting so I was going threw the wiring to find out why and as I was doing this I noticed ohe of the three wires that are on the plug for the coil was broke fixed that and my tach started to work again. So I would check those wires. Good luck

Good sugesstion but wont work your 98 has one coil the 05 has coil for each cylinder, also like I said there is either a recall or tsb out for the guage cluster for that year call a dealer and they can tell ya more

big red · March 15, 2012, 07:54:14 PM

Before you spend tons of money get new plugs. The 92 in the drive way we put new plugs in and it started missing. Put $800 into parts then replaced the plug in the port missing and no more miss. bad plug from the factory.

Flexpipe · March 19, 2012, 09:36:46 PM

Thanks for all the help.

I finally figured out that the injector was bad on number 8 cylinder. But I did swap out the Bosch plugs and wires for AC-Delco plugs and wires I won't make that mistake again of buying the Bosch

. I used to buy Bosch plugs. Quite a few years ago they made a good plug.

Flexpipe · March 19, 2012, 09:42:06 PM

As for the instrument cluster. I asked the local chevy dealer and they told me that there was a recall on them but it has to have less than 80,000 miles on it.

since mine has 95,000 miles they won't fix it. And they told me it would cost $400.

I don't think so

xjs3667 · March 20, 2012, 12:15:32 AM

Quote from: Flexpipe on March 19, 2012, 09:42:06 PM
As for the instrument cluster. I asked the local chevy dealer and they told me that there was a recall on them but it has to have less than 80,000 miles on it. since mine has 95,000 miles they won't fix it. And they told me it would cost $400. I don't think so

Wow thats messed up

01vortecpwr · March 20, 2012, 01:26:29 AM

my 5.3 engine started blinking the other day found out it was bank 1 sensor 1 oxygen sensor. no voltage.

01vortecpwr · March 20, 2012, 01:27:11 AM

*engine lite*

Eroq · March 20, 2012, 01:32:10 AM

Quote from: big red on March 15, 2012, 07:54:14 PM
Before you spend tons of money get new plugs. The 92 in the drive way we put new plugs in and it started missing. Put $800 into parts then replaced the plug in the port missing and no more miss. bad plug from the factory.

older gm motors and newer are completely different monsters, need to run platinums in all vortecs. higher energy ignition will burn up copper cores, you'll need to replace them a hell of a lot sooner. i run nothing but AC delco. cant beat what came from the factory. same thing with ford and using motorcraft parts.. cant beat it!