Will Engine misfire cause EGR, & o2 codes?

[boarder]

Trying to fix a very slight engine stumble at higher rpm and under load.
1998 4.3. Getting a 0300 code(random misfire) & also EGR, and both o2 sensors showing codes, as well as a vacuum code. Replaced Plugs, wires, cap,rotor, pickup coil, fuel filter and fuel pump recently.

My question is: Is it possible that this misfire/stumble is caused by egr or o2. Or vise versa, the egr and 02 codes are resulting from a misfire.

Thanks in advance.

[mike2004tct]

Originally Posted by boarder

Trying to fix a very slight engine stumble at higher rpm and under load.
1998 4.3. Getting a 0300 code(random misfire) & also EGR, and both o2 sensors showing codes, as well as a vacuum code. Replaced Plugs, wires, cap,rotor, pickup coil, fuel filter and fuel pump recently.

My question is: Is it possible that this misfire/stumble is caused by egr or o2. Or vise versa, the egr and 02 codes are resulting from a misfire.

Thanks in advance.

I had a similar problem with a V6 Pontiac engine to what you describe.
A faulty EGR valve caused stumbling at a steady pace/speed.

You can remove the valve, and check the pintle for a buildup of carbon.
It may cause the valve to not close properly.

[MT-2500]

What are all of the the code numbers?
How ramdom is the missfire?
Full or part time miss or dead miss?
What cylinders are missfiring?
A egr valve prblem can give a miss and mess up O2 sensors.
I would check out egr valve for carbon build up and not closing to start with.