03 Yukon Misfire

[Chevykid404]

I am completely stumped on finding the misfire on my 03 Yukon 5.3L. I have a misfire that I cannot fix. Due to the misfire I cannot get my emissions done to register the Yukon. I just recently replaced the fuel pump, fuel filter, fuel injectors, coil packs, spark plugs and wires. The codes on the ODB2 reads P0200, P0300, and P0332. I am at a loss as to what the issue is. Does anyone have any experience with this issue? I really need my Yukon and don’t want to continue throwing money at parts and it do not fix the problem. My Yukon is burning gas fast and when stepping on the accelerator is not getting all the power behind it.

 

[Scottydoggs]

p0334 is a knock sensor code, 300 is random misfires, p0200 is cylinder two injector circuit.

check over the wire to the injector plug, and the harness for damage. you can also swap the injector with the one next to it to see if the code moves to a p0400 aka cylinder 4 thats next to cyl 2, if the code moves that injector is bad. you can also take small bulb like a parking running light from a head light, push that into the injector plug fire the engine up see if the bulb flashes. test light also works for this.

depending on miles clogged cats can cause the p0300 multiple misfires. cause the lack in power and sucking down gas.

 

[Fless]

Save your old parts since they may be better than any aftermarket parts. No-name injectors, especially, may cause more problems than they solve.

Follow the link below for the P0200 diagnostic procedure, but first verify your specific vehicle and change using the links at the top of the browser window.

P0200 — 2003 GMC C 1500 Yukon 2WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2003 GMC C 1500 Yukon 2WD V8-5.3L VIN T.

charm.li

 

[alpha_omega]

The knock sensors on those are kind of a PITA to get to. They are under the intake and really should be sealed (dammed) with some silicone after installing to prevent water intrusion. Plan to spend a good couple hours or more if you’re not familiar with vehicles and plan on doing it yourself. It’s an easy job, just tedious.
You’ll want new knock sensors and new intake gaskets. Possibly a new spark plug and injector depending on how far you’ve driven with it missing.

Take a picture of your RPO code sheet (found in the glovebox or maybe behind the passenger sun visor) and have your VIN. You’ll want both when you go to order your parts (VIN because the parts are different being a regular vs flex vs hybrid - and before anyone says otherwise, yes I know the hybrids weren’t out back then).

 

[Fless]

If you do the knock sensors, use GM OE sensors and a new harness. When you reinstall the knock sensors be sure to add the RTV PARTIAL dams in the right place:

02-06-04-023A Chevrolet Technical Service Bulletin

02-06-04-023A Chevrolet Technical Service Bulletin

www.tsbsearch.com

(this TSB is for the rear sensor replacement, but the dam also applies to the front sensor)

 

[Tonyrodz]

I had a misfire, turned out the injector harness had a broken wire. Fixed it and no more issues. Check yours.

 

[Scottydoggs]

and tq them delco sensors to 14 ft lbs. no more no less. it actually matters.

 

[Fless]

Here's a link to knock sensor testing. Note that the sensor resistance is given as 93 to 107 K Ohms.

How To Test The Knock Sensors (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon)

GM 4.8L, 5.3L, 6.0L Index of Articles

easyautodiagnostics.com