Replaced Intake Manifold Gaskets - Now Rough Idle...Help!

[Rockmiller]

Here is my dilemma. I am working on a 1999 Olds Alero with the 3.4 V6. I recently replaced the intake manifold gaskets both upper and lower.

Upon re-assembly and starting I found that there was a rough idle and shift issue. The rough shift issue I fixed when I replaced a MAF vacuum hose that I cracked during the gasket replacement, but the car is still running rough at low idle.

The car pretty much bucks when stopped, in DRIVE, at low RPM(500-750). I have replaced the plugs, wires, and O2 Sensor, and it is still doing it.

I saw one other post out here with some thing similar, but they had a cracked intake vacuum line. I have no more cracked lines.

I also had the SES codes ran at Autozone, and the car had 2 codes, one saying it was running rich, and the other flagging the O2 Sensor, a misfire, the MAF sensor, or the MAP sensor. The second code obviously explains the first code.

So after reading the other parties issues I am starting to believe that it might be something on the intake, but the MAP sensor was fine before the gasket job, and the the flow is correct. Could it have went bad during the disconnection of the clip?

Any ideas out there on what is going on? Really would like to get this job done.

[BNaylor]

Welcome to AF.

It would help to post the diagnostic trouble codes. Have you checked engine vacuum with an automotive vacuum tester gauge (0-30 in hg). Good vacuum is 15 - 22 in hg.