2008 Suburban misfire cylinder 1

Hoping to get some help getting my suburban running again. It is the 5.3l LS 1500. Unsure when the last tune up was, i haven't owned it very long.

I have a Misfire code for cylinder 1. Its running rough and i have the Stablitrack and traction control warnings as well.

What i have done:

- swap plugs for 1 and 3 with no change
- swap plug wires for 1 and 3 with no change
- swap coil packs for 1 and 3 with no change
- swap injectors for 1 and 3 with no change.

where do i go from here? compression check?

the plug from cylinder 1 was very clean but also had oil on it, smelled of unburned fuel.

from what i have read the stabilitrack and traction control issues are caused by the misfire?? is that correct?

Thanks-

I'm not familiar with that engine but if you have a dizzy cap is check or replace that next. A compression check is also totally logical

Those engines don't have a distributor. Its a distributorless ignition system (as you should guess because he said coil packs). It's an LS V8 engine.

OP
I would highly doubt the stabilitrack and traction control could cause a misfire.

Check to see if cylinder 1 is even getting any spark.

Also oil on the plug could mean a balve issue, hook a vacuum gauge up to the intake and watch the needle. If it bounces youve got a valve or c issue. I saw a 350 wear out 1 lobe on the cam and it took 2 days before someone did the vacuum check. It was too late though as we already sold the owner a new motor. Of course check compression also

OP Here.

I check vacuum and compression. Next thing.

If it is a valve issue does that mean pulling the head off?

Why do you drive a suburban?

>pulling the head off?
Probably cheaper just to swap in a junkyard LS.

because i have 4 kids

I live in Panama (like the canal one not the beach one)

No junkyards here. Also the mechanics are horrible, which is why I'm looking at doing this myself.

One more thing. The misfire seems to stop if its above 1500 rpm's. Does that help identify any problems?

Do a leak down test to confirm no mechanical problems. I'd change the all plugs, check, then do all the wires, check, then do the coil. If it's still misfiring then idk.

Wear a fucking rubber jesus christ

ha. they were all planned.

I'm guessing you don't have access to an obd2 reader?

could be a coil driver in the ecu have you verified no spark? use a spark tester or stick a screwdriver in the end of the wire prop it somewhere so there is a gap between the shank and something metal (DONT HOLD IT). Crank the engine and see if there is spark.

the fact that it goes away above 1500rpm makes me think it is a fresh air leak, you can start the engine and spray starting fluid around the intake manifold and throttle body. if the engine revs up you've found your leak. could be a stuck canister purge valve or many other things to do with the emissions and evaporative systems

although it could be a stuck canister purge valve or many other things to do with the emissions system.

I have the Ease Diagnostic software on my laptop and the obd to usb cable.

I have not physically verified the spark but i figured swapping plug/cable/coil on 1 and 3 would take care of that problem if it existed.

I do have an evap code, but its been there a long time. I'll check that code when i get home.

the local mechanic said the oil on the plug was "muy malo" but he doesnt have gauges to run a compression test.

Im asking around to see if someone else has some.

Compression check first. Have you hooked up a multimiter to the coil 1 connector and checked that way? Fresh air leak is possible as well as is weak power to the coil though the latter is a shot in the dark, usually you have power or not. Sprat carb cleaner around the intake plenum and see what she does. If it idles up, there's the issue. Just a thought as well, have you swapped number 1 and 3 injector? It may be pushing a code for a Cyl 1 misfire but your software could be crap as well meaning it wouldn't be able to check each injector and would register it as a generic misfire.

I will check the voltage at the coil connection.
Also i will check for fresh air leak.

I did swap the 1 and 3 injector and that had no effect.

Im still trying to figure out everything about the software, a bit over my head with it. i did figure out how to get live misfire reading though, which is cool.

Bumping to save this thread and save OP from having to make a new thread and do this all over again.

thank you. how often do they purge?

>the local mechanic said the oil on the plug was "muy malo" but he doesnt have gauges to run a compression test.
Jesus christ, get a better mechanic.

Preferable someone with late model certifications.

don't let it get to the last page. Everything is eventually purged once interest has waned.

bumping for same reason

>the plug from cylinder 1 was very clean but also had oil on it, smelled of unburned fuel.
oil on the electrode?

How much? Oil on the electrode will prevent spark and therefore the cylinder will not fire. Most likely this is caused by a valve issue. Best case you have a bad valve guide seal. badder case a bad valve seat or vavle. You can replace a seal without the head in place (i think). It is possible though that you have a bad ring or a damaged piston. A cheap way, without a leak down kit or compression check, is to run the engine and open up the oil dip stick.. if its puffing out air.. you have bad rings or a bad piston.

Good news is head removal on a pushrod is pretty durn easy.

this much oil

evap code is p0449 evaporative emission system vent valve solenoid circuit

hmmm i don't think that would be enough to prevent spark and combustion... I could be way ass wrong. In my case it was drenched with oil with oil between the ground and electrode.

I would verify spark. Just because the coil is o.k. doesn't mean the signal to the coil is o.k.

no air puffing from dip stick tube

Is that a new code along with the cyl#1 misfire code?
also whats the mileage on the vehicle?
do you hear any ticking?
and how long after obtaining the vehicle did it start to give problems?

Like i said earlier. I'm in Panama, in a rural area. there are 3 mechanics here. One is smart but doesn't have much tech, the other has the stuff but it known to fix one thing and break another, and the third just isn't very good. The closest chevy "dealer" is a 5 hour drive across the mountains; which i dont think the suburban could do in it's current state. And even then, the dealer isn't much more honest and will definitely not be familiar with Suburbans. everything here is 4 cyl or diesel.

No, the evap code has been there for over a year. so i dont think its the source of this issues.

86000 miles.

ticking. Ok backstory.
>Burb running well
>developed tick
>took to mech#3 (who i used to trust)
>He fixed tick, said it was lifter on even bank
>Also changed oil with wrong oil, 5w15 instead of 5w30
>Runs really rough when he brings it back
>he puts correct oil, runs better, but still shitty.
>i hook up to obd and find misfire #1

As of now there is no ticking.
So, im not sure if what he did broke something. Seems like really odd timing for something new to develop, but what can i do.

I had the car about a year before problems started.

I tested spark with the screwdriver method and got zapped.
Need to get my multimeter back from the neighbor and will test the coil input wires.

Carb cleaner can was empty so need to get more and then i'll test for air leaks.

I've been reading about issues with the AFM on the 5.3's. Something about hydraulic lifters seizing due to low oil pressure? Anyone know about that.
But a seized lifter would make a loud tap right?