pull the valve cover, it has to be somthing in the valvetrain then

Time for a cam swap while your in there!

x2, that is more than likely where the issue is.

Yup, Chris always use to come fish out at my house. 25 cent on Bent pushrod

I told tech 20 times it was valve train. Whet do I know lol.

I didn't say jamie did I?

Nope and I didn't mean to either. JP rather. Sorry.

I don't wan't to get too deep into this, but the GM knock detection can determine which cylynder is knocking by first, considering which sensor is triggering (front/rear or in later years left/right). Then, it will use the current crank position and firing order to determine the offending cylinder. It also can control firing events on a cylinder by cylinder basis.

As far as misfires go, understand that the PCM does not detect a misfire, per se, it only detects rotational speed variations between predicted firing events. So any condition that causes a variation in rotational speed can be viewed as a "misfire" by the PCM. It doesn't have to be an actual lack of or incomplete combustion.

I'm in no way supporting the techs claims, just wanted to clarify a few things.

I hope you get it figured out soon. These situations can be very frustrating.

Good luck.

jaime i agree, this is why my first suggestion was unplug the knock sensor harness, which would make the pcm pull timing automatically and see if there is any change (besides less power)..... if it still has the misfire then its not false knock produced by the headers and they need to look further.

if it were the headers causing false knock it wouldnt show as a single cylinder misfire..... so regardless its a cop out....

I just don't know what to do. Do I call them today and tell em i'm gonna come get the truck? Or do I let them figure it out?

So tired of thinking about this......

Why not try Crews Chevrolet and see what they say?

That's what I was thinking, but Hendrick gave me a rental car.....which on the way to work decided it was going to start going crazy and saying stability control is broken...>WTF.

I'm wondering, if I go back and demand my truck back, will they make me pay for the rental?

Need some advice guys.........

Service manager called me, and says that they can't figure out what's going on. He now wants money to change plugs/wires out to stock, and go from there. Not only that, he's asking if i'm gonna "help him out" with the work they've already done?

His specific quote "We can't find anything NON-OEM that could be causing this."

YET THEY STILL HAVEN"T PULLED THE VALVE COVER? WTF?

What am I supposed to do? Let them put plugs/wires on it? Problem is, clearance issues with LT headers and stock wires, #2 and #7 primaries will melt the wires. And they want to charge me?

HELP

Get some protective boots for the wires. The stock metal ones should work, or even any autoparts store sells them. Worth a shot.

There are heat socks on the PCMforless wires now. I just called em back and said to put plugs/wires on it with my socks. If it doesn't fix it, I told him I wanted it returned to the way it was and for them to figure out what's going on.

Thats not the problem if you switch the wires around and changed the plug already and it stayed the same. They aren't gonna figure it out. If they really wanted to figure it out it would be fixed by now and you wouldn't be driving that pos HHR. The problem is on one cyclinder but they want to put stock shit on all of the cyclinder and then they are gonna @ss rape you on the price of plugs, wires, and install. The problem with most dealerships is that some of the techs dont know shit about diagnosing a problem they just throw parts at it until they get lucky. Take it to somebody who knows what they are doing and pay them to diagnose the problem. It will cost the same as the stock plugs, wires, and there labor. talk to Gerald maybe he can figure it out.

yea i say Gerald too. he found some strange shit on my mustang. depends on if he is up to the challenge, or has the free time.

What exactly did you change when the miss fire started?

I did work (tuning) for several of the dealers in Charleston/North Charleston when I had my shop in North Charleston. After being the dealers and dealing with there tech's I lost faith in there mechanical skill's.

Well, all of this started after Gerald had my truck for a week or so. He did trans build,longtubes with catless y pipe and plugs and wires.

About 600 miles later this started. I never really got on it hard during the first 4-500 miles, but a week before I noticed this issue, I hammered it a couple of times on the interstate fucking up a dodge neon and never had one issue.

I'm at a loss. I really really hope that stock plugs and wires DOESN'T fix it, cuz if they do I gotta pay for them and eat my words.

Oh and service manager had the followin to say about the tech: "he's one of my top guys, and surely the most experienced with MODIFIED vehicles."

Intake and exhaust is modified now? WTF? I put intake and exhaust on my 07 silvy a week after it rolled off the lot? Everybody does!

Confucius say; the tech should have found the bad muffler bearing a long time ago....

seriously, I'm not feeling like the dealership is going to warranty your actual issue if they ever actually do find it. So I would take it to somebody more performance oriented and get aftermarket go fast goodies vs stock stuff.

With an aftermarket converter you can get false miss fires. I usually do a crank re-learn and also have to adjust miss-fire tables in the tune for vehicles with cam or after market stall.

Does it regardless

I wouldn't even bother messing with the dealership. Ford would void the power train warranty in a heart beat if you brought in your vehicle to them with all these mods. No doubt you also have a tune on it?

Did your tuner do a crank re-learn after you installed the new pcm? Thats the first thing I do when I install a new pcm in something. I have seen crank re-learns fix some weird issues before.

Truck is untuned at this point.

Crane makes a valve spring compressor tool you can use while the head is still on the block. Looks like it compresses both intake and exhaust valves at the same time for one cylinder.

http://www.summitracing.com/parts/CRN-99472-1/

Well, i'ts now 1PM and they haven't called me. Think that means it still won't run with stock plugs/wires?

That little friggin thing costs $114.95? WTF? I'm in the wrong business.


And Gerald, does that mean that you concur on our diagnosis of valve train and not ignition?

Maybe it is just a coincidence, but this is why I'm afraid to tune my car, or add some other parts.

get a good local tuner (JP) that is willing to help you out and there isnt an issue

tell them to do a crank relearn (has to be done with efilive or a tech 2) and see if it fixes the problem

That's why I took it to them, man. They're the professionals. What do I know, right?

I suggested it yesterday, and he said he did it. We'll see I guess.

From what I've been reading in this thread, the above statement along with many other are incorrect.

430 and not one phone call all day. Hmmmmm......

does your phone make calls too or just receive them? If it can make a call out than call them and check. Don't wait around for them to call

The cost of the tool will be chump change compared to what Hendrick will probably end up charging you for chasing ghosts on their end. I believe JP has one of those tools that can be borrowed for a minor fee to keep from purchasing one outright.

Valvetrain is about the only area left to dig into other than unplugging the knock sensors via the plug at the rear of the intake and going for a ride. Unplugging the knock sensors will back the timing up some, but still leave enough to twist up to the top of the tach.

It isn't all that bad to get a valve cover off. It just looks intimidating with the coil pack rack and heater hoses run across the top. Its probably just as hard to get the rear plug out to put an air line to it to hold the valves up.

Rob (MonteC) might lent you rent his spring compressor.

I bought the right tool made by rsi(i think) for the ls engines when I did my z06 spring swap. You will be hurting if you get a cheap one. The right tool for the job makes things so simple.

What size converter? I had to have my misfire tables adjusted because it was breaking up at 4500 rpm