For a while now I've noticed that my 1999 Trans Am ran a little rough while idling. About three months ago, I had the entire fuel system cleaned as my mechanic thought that this was the problem. Well, it helped but didn't completely fix the problem. So I took it back in yesterday and my mechanic checked nearly everything. He advised me that my car is showing intermittant misses in all cylinders and he wasn't sure why. The coil, compression, and fuel system tests all checked out fine.

So he called GM tech support and they advised him that it sounds like "Sticking valves?" So, he ran top end engine cleaner through it as GM advised him that this might fix the problem. Well, the meter is still showing the misses and the car still idles a little rough. He advised me that the next step would be to pull the heads and see if the valves are sticking, which will be an expensive venture.

I'm starting to think that my mechanic is a quack and he really has no clue about the LS1 engine.

Any input from you guys would be appreciated.

 

Well first off he should be checking the PCM codes, they will tell him what the problem is, or very close to it.
It sounds like he is not that good, I would take it somewhere else, and see what they say.

 

With as many miles as you have the guides have enough wear there is no way the valves are sticking. The GM dealer don't know what they are talking about.And don't let people tell you carbon,unleaded don't build carbon but severe oil burning will..
I would believe worn seats,and you need a valve job but not likely.If it ain't shaking the fenders I wouldn't worry with it,it could be an accumalation of a little of all the things that make one idle rough.Now when I say rough I mean a glass of water on the intake filled to 1/2" below top and it is sloshing water out.If the compression checks and you haven't tuned it lately I wouldn't be concerned.

The basics of a LS-1 are no different than an LT-1,there may be a few different tricks but they are basicly the same.

 

Yeah, I lost a lot of faith in the guy when he told me: "This is engine was only designed to be worked on by the people who developed it." Well, my mechanic is a GM mechanic. Did I miss something? Didn't GM make this engine?

 

rough idle, random misfires in all cylinders, sounds like plugs/wires/coils ---> replace in that order.

 

stuck valve ?open or closed? and what made it stick in the first place, glue in the intake? pleeease enough allready. stuck valve means colapased lifter broken rocker or broken pushrod if stuck closed and if open the piston will proabably wipe it out when it hits it on the up stroke, either way it will GREATLY affect the preformance of the motor beond just a rough idle. i bet that parts changer would love to get that ls1 apart so he could never rember how to put it back together again. be very careful of the abaility of that parts changer!