Muffler suck

[madsav]

just finished doing a head gasket on my v6 both sides have a compression of 150psi per cyl so im pretty hapyp with the job done but ive noticed it has a very small miss and when u have your hand near the muffler tip u can fell it blowing out of course but ever so often it sucks back in not sure as to why it does that

[Dum*P*ster]

The Buicks will always have a very faint miss.. its just what they do

However.. it wouldnt hurt to change your Spark PLugs & leads

[strgas]

possibly a burnt valve causing the suck back ?

[madsav]

Any other reasons that could cause suck back? if it is valuves is there anyway of fixing it without removing the heads again

[BoNeZ-01]

Take it for a drive, somewhere away from heavy traffic, where it's safe to listen to and feel what the engine is doing at different speeds and rev's, see if it's affected by the 'miss'.
If it is still missing after you get back, check all of your plugs, have a good look at them one by one, after it's cooled enough to take them out.
Your plugs are one of the best indicators of how you engine is running, with the advantage of showing you any variations in efficiency between different cylinders.
Maybe even make a little note of how each one looks and what number it is as you inspect them, so you can compare them each other.
If the performance, efficiency, and economy is not affected by the miss, then it may be nothing, as no engine has a 'perfectly flawless' idle, there is always a little bit of variation.
It could also be to do with the exhaust side of things, as was correctly explained to me here in JC about how exhaust pulses work.
That 'miss' could be a variation in the flow of the gases out of the system, or it could be a number of other things, or it could be just nothing to worry about at all.

[madsav]

the little miss is only slighty there under throttle,
But noticed at random times when slowign down car stalls

[BoNeZ-01]

hmm.. If all you did since you noticed the miss, was put new head gaskets on, then maybe it's just dirty injectors?
Otherwise I'd be checking the codes again after your drive, could be Crank Angle Sensor, oxy sensor, or could even be a bad plug or lead, coil pack..?
But I'm just guessing now..

[madsav]

only code im getting is 24 says somthign about speed sensor not work etc other then that the computer is clear , i changed the spark plugs and leads gonna check the coil pack next