: Did some work, now getting PO300, 302, and 306 codes

Stray Bullet
09-07-09, 12:08 PM
Hello all,

Yesterday I changed the timing belt and the valve cover gaskets on my 99 Catera.

Everything was put back together, but when I started the car I get some misfiring. But the strange thing is that it only misfires at low RPM's. When I drive the car it's flawless. It's only when I come to a stop long enough for the RPM to get sub 1000.

Has anyone ever had this problem?

Also, does anyone know where I can find a diagram of the vacuum lines? I'm thinking I may have some in the wrong places.


09-07-09, 06:57 PM
I have similar symtoms on Bank 1. Checked my timing belt- OK, vacuum lines- OK. I may mess with it further and figure it out.