Need Help Badly!!!

[Jason97T/A]

Hey guys, I took my car to the dealership out here. My car has been cutting out really bad under acceleration, and has had a really rough idle, and kind of a sputter in the exhaust. They said it had a mis in a couple cylinders. I dont remember which ones. He said he checked the ignition, and injectors, and put new spark plugs in, but the ignition and injectors were good he said. Now they told me they would have to tear into the engine to see what the problem is. Big $$$$. I just had the cam and lifters and all the bearings replaced for about 3 grand a year ago. Also had the opti replaced at the same time. Do you guys think this could be a problem internal or what? Any ideas, are greatly appreciated. I have a 97 Trans am with 105xxx. It has a flowmaster system with no cats, LT4 KM, Removed MAF Screen. I need all the help i can get!! I cant afford to have them tear into the engine again.
Thanks
Jason

[Joe 1320]

It is possible that a cam lobe or two has gone flat. Collapsed lifters would generate a ticking sound, so if it's quiet, probably not that. Have they done a compression and leakdown test?

[hotwhip9]

Find another shop and get a second opinion on it, and do simple things like change the fuel filter, i know that can cause a huge lag in acceleration if it needs to be changed.

[N20LT4Bird]

I agree with Joe. You've gotta do a compression test on the cylinders with the miss. If you've got compression, there's no reason to tear into the engine right away. There are quite a few other external possibilities to check into. Checking the fuel and the spark at the individual cylinders etc..

If you don't have compression, then move to a leak down and find out where it's going. Maybe its something simple like a misadjusted rocker. Who knows?

[Jason97T/A]

Originally posted by Joe 1320
It is possible that a cam lobe or two has gone flat. Collapsed lifters would generate a ticking sound, so if it's quiet, probably not that. Have they done a compression and leakdown test?

I just had the cam and lifters replaced about 5xxx ago though. So I don't see how he could have screwed them up and 5xxx miles later the problem comes back. The engine doesn't have any abnormal sounds.
The thing that has me is how it is two of the cyclinders. To me thats kinda wierd to have to cyclinders missing. That tells me that it is probably a wire, the coil, or perhaps the opti AGAIN, even though that was replaced 5xxx miles ago.
What other things could it be internally?
What other things externally that hasn't been mentioned can cause a miss?
Any help greatly appreciated.
Thanks
Jason

[Joe 1320]

Originally posted by Jason97T/A
I just had the cam and lifters replaced about 5xxx ago though. So I don't see how he could have screwed them up and 5xxx miles later the problem comes back. The engine doesn't have any abnormal sounds.
The thing that has me is how it is two of the cyclinders. To me thats kinda wierd to have to cyclinders missing. That tells me that it is probably a wire, the coil, or perhaps the opti AGAIN, even though that was replaced 5xxx miles ago.
What other things could it be internally?
What other things externally that hasn't been mentioned can cause a miss?
Any help greatly appreciated.
Thanks
Jason

Jason, I hate to tell you this bro, but I've seen parts replaced that fail shortly after because a mechanic will treat the system rather than the cause. If the reason the original cam went flat wasn't found(like a partially plugged oil passage) and corrected, the new part will fail the same way. I've also seen a relatively brand new opti fail as well. If it were the coil, would be system wide misfire and would not be relegated to a specific cylinder or two. It could be a plug or plug wire, it could also be the opti. After troubleshooting the rest of the ignition system, IMHO, I would put a dial indicator on the valves and check valve lift, I would do a compression check as well as a leakdown test. This will at least verify the internal parts are not the culprit before the motor is really opened up. If you're not too handy in the mechanic skills dept, it never hurts to get a second opinion. If you were close by, I would say bring it by my garage and we'll go through it, it's really tough to diagnose this stuff without having hands on. It's like a doctor giving you a diagnosis over the phone without an exam.