If it says misfire have you tried replacing the spark plugs at all? you can get a set of a ngk tr55 at o'rieleys for like 10 bucks. start with the small stuff first if thats not it then change the spark plug wires. i just put a new motor in my car and had the same problem replaced the wires and plugs end of that.

 

They said that they eliminated everything electical. Plugs, Wires, etc...

 

Update. Stealership just called and said the programming for the computer is not stock and the car was running rich at idle and the computer would try to lean it out. They also said that one of my O2 sensors was bad that they replaced. Does any of this make sense to anyone.

 

If its running rich that could possibly make your plugs foul out.

 

Get your car away from the dealer. I've never had any luck with dealerships when it comes to non warrenty repairs.

I agree with headed. Get new plus and wires.

 

It the work that they have just done does not fix the issue it could be a valve. Common valve issues are mainly present at an idle and can disappear as the RPM's increase. As the engine moves through the paces at a lower rpm slight imperfections have a larger effect on the way you engine runs but as you increase engine speed those imperfections dont have the same amount of time to effect your engines performance therefor they may not be as bad or may disappear. A bent valve is a possibility. But you need to do a leak down test. I would pull the valve cover yourself and make sure you check your valvesprings as well. Keep us updated.

 

The pushrods bent for a reason. The valves most likely hit the pistons and the weakest link gave, and often times it's only the pushrods. Sometimes, it's a valve. A very slightly bent valve with a poor seal would show only a very minimal loss in overall power, but would produce a rough idle. The dealer diagnosed the problem correctly, but your stubborn beliefs about "stealerships" won't let you see that. So either go with their correct diagnosis, or listen to the people above that go by the "stealership" mentality and put plugs and wires on it to fix your low compression issue

 

Step 1.

Step 2. Pizza and beer is way cheaper than $2000 to pull the heads. Post up a link in your regional section asking for some help. I'm sure people will help you out. We do it all the time down here.

 

i bent 3 valves last year and the car did not make noise, didnt even run too bad, didnt run right though. Def do a leakdown test, or go to another shop. Not all mechanics are out to do anything to make a buck. I hate that stereotype. It depends on where you are if you are in the city then yea you are probably going to get screwed. I own a shop in a small town and you have to treat everybody right, that is how you get business. I had a van today that had rear a/c lines leaking on it well i had just gotten a new tool like the dealers have to repair the lines. didnt work so well. I had 5 hours in scewing with it, the customer will not get a bill, that is just the way i do things. And i know he will be back cause i treated him fairly, yea i lost my ***, but why should he pay for a job that did not fix his problem??

 

"2,000.00 to pull the heads and check it"

I know a guy who'll replace both your heads for $500 cash on the labor. Too bad his kids will be playing inside the whole time and the cats will be sleeping in-on-all over the car!

 

i thought the rev limiter was supposed to PREVENT the car from over revving and causing damange to the valve train? If not, why have it? Why would GM set the rev limiter so high that if you hit it by accident (like many of us do with our M6), it still causes damage? Why not set it to like 5800 RPM (stock); don't we make our peak power at 5500?

 

Yeah people don't know all the jobs you eat and time you loose when being an honest mechanic. I did it for a long time before I got another job a few years ago. I don't trust mechanics either. I think it's just that I know what I know and don't know, but someone else I don't. I was trying to get a set of wiper blades on my car the other day and the auto parts guy was trying to help. I took them from him.

lcars,

If you don't want to do it yourself ask around and find a smaller shop that does good work.

It would be best to find out what cylinder is missing. It would be a little easier and faster to find out what the problem is. Good luck and keep us posted.

Jason

 

The reason why I'm calling them a stealership is because the first time I took it to them they pulled the driver side valve cover off to check the pushrods that I had just replaced and they said there is nothing wrong. They charged me over $300.00 just to do that. They reset the computer and said it must be that one of the pushrods got stretched and after checking them and putting them back and torquing (sp?) everything back it fixed the problem. Well it didn't and the SES light came back on so I took it back to them and they told me it was a vacuum leak from the EVAP hose and the metal tube on top of the intake wasn't sealing properly so they fixed those by replacing the EVAP hose and putting some sealant around the end of the tube going into the intake. Again they charged me over $300.00 and had the car all of last week. I picked it up yesterday morning drove it home and parked it in the driveway and let the car idle. The light again came back on so I immediately took it back to them. Yesterday afternoon they called and said that the tune on the car is not stock and it runs rich while at idle. They said that one of the O2 sensors near the front of the car was bad and thats why the the light kept coming on. They replaced the sensor and said they let the car idle for 20 minutes took the car for a short drive and then let it idle for another 30 minutes and the light never came back on. They now want to charge me over $200.00 for that. They originally thought that the car was losing compression and thats why they thought it was a valve and thought they would have to pull the heads but now they said everything is fine. I'm picking up this afternoon.

 

dude, I work at a dealership in MI, Sellers pont./gmc in farmington hills if your in the area. if you need honest work you can bring it to me. I got lots of people round here to back me up. and I do tons of performance stuff.

anyways, the first 2 rounds of "fix's" SHOULD be returned to you, as they did nothing to fix the problem. you dont charge someone to remove the pushrods unless you have a reason to do it. in that case, remove the pushrods from the cyl. thats down on compression.

not all dealership mech.s are ripoffs. true, some are, some dont know whats really goin on, but the majority are like me, honest people trying to make a living.

all that being said, the revlimiter is not fast enough to stop your engine from spinning too high when your at the top of a gear, and shift BACK to a lower gear. try that with an MSD revlimiter and you'll have the same thing. bent pushrods, and probably bent valves.

couple people have already noted that bent valves, if very slight, will not have any symptoms off idle, but will misfire at idle. thats true. and a leakdown test is the ONLY way to know for sure. think of the compression test as a rough test. now that points out the obvious, but might not show you very slight valve sealing problems. the leakdown test will show you exactly what percentage is leaking, and will help you figure out which valve is bent by listening to the intake and exh. for the airflow.

so, IS the tune stock or not? you didnt tell us. if the eng. is running rich, then your fuel trims are in the negative, right? I know you probably dont know that, but Im curious if the person who told you that knows what there talking about? sometimes, the service writers tell customers things they "think" are accurate, when really its not. it drives us tech's crazy cause sometimes it makes us look like we dont know what were talking about.

you should try to get some of your money back for all the work they did that ddnt fix anything. you wont get the diagnostic time back, cause you should pay for that. but the repairs they did that didnt fix anything should be refunded, parts included.

chris

 

I don't know if the tune is stock or not. IThe gentlemen I bought the car from said he never had it dynoed or tuned. I'm assuming not though because the rev limiter should have engaged at or near 6000 rpm but i don't remember it doing so. I also agree that i should be entitled to some money back as the sensors should have been one of the first things they checked IMO. I'm not going to bitch them out till I ensure my car is working and get it far away from them. After its all said and done I won't be taking it back to them. I live in Jackson, MI by the way not too far from Farmington Hills but far enough.

 

yay your a couple hours away. anyways cant wait to hear exactly what they did to "fix"it.

 

Update: I picked the car up yesterday afternoon. I drove it to the car wash and had the car washed. I drove the car home and let the car idle in my driveway and sure enough the SES light came back on. I immediately called the dealership and told them what happened. They told me not to bring the car back immediately as they will need to do some research. My plan is to call and speak with the manager today and tell him whats been going on. I have found a local guy here that appears to be reputable. www.dynoserve.com I expect the dealship to pay up to the amount that I paid them to "fix" my car to this gentlemen as I no longer trust them to do their jobs.

 

well they wont pay the other shop, but they should def. refund your money for any repairs that didnt fix the problem. what exactly have they charged you for?

 

They charged me the first time for diagnostics and to pull the valve cover on the driver side of the motor off to check the pushrods. That was over $300.00

They charged me over $300.00 the second time to replace the EVAP hose.

They charged me $250.00 this last time I brought it in to replace the O2 sensor.

I don't expect them to specifically pay someone else to work on it I expect them to refund my money for the charges so that I can pay someone else to work on it as they haven't identified the problem nor done anything to fix it.

 

damn, they did rake you over the coals it seems. course, not being there to see what they saw doesnt mean the evap hose and/or the 02 sensor werent bad, but point is neither of them fixed the problem. so unless they told you specifically this might not fix the problem, but these parts are bad because.........., they should refund you all that money. if you had brought your car to my dealership, Im positive you wouldnt have had to pay for those repairs.

and, they should have only charged you 1 time for diagn., then for the time to do the compression test. and didnt you say they checked the pushrods AFTER you replaced them? why on earth would they do that?

I bet you money you got a bent valve though.

oh, and dont have to ever replace ign. parts to guess at fixing a misfire on an LS1. you can just swap coils, wires, plugs between cyl.s and see if the misfire follows that part to the other cyl.

if they dont refund your money, Id be looking for a lawyer for some advice. my buddy john (another member on this board) just moved his office from ann arbor to livonia, but he still does work all over the place. I could send you his email if you would like.

chris