Runs at half power till warm

I have a 1997 chevy 2500 with a 5.0 with 115000 miles. I just put new plugs wires coil ditributor fuel pump and two o2 sensors in it. I was getting codes for o2 sensors and now I am getting p0307 number seven misfire. As I said it has new plugs and wires. What I was wondering is why it would run at half power or barely run and then take off after a couple of minutes. The check engine flashes until it takes off. Any ideas much appreciated.

Thanks

Peter

What kind of plugs did you use?

307 is a engine misfire on no 7 cylinder.
Is no 7 plug getting good hot blue spark and is plug wet on end when missing?

Check all sensor readings and fuel pressure for up to par.

The plugs were ac double platium. I will check the pressure and spark. I had a mechanic put the plugs in but I will double check it. The rest of the stuff I read the codes and put in.

Thank for reply.

Peter

You are welcome and let us know how it goes.

The plugs were ac double platium. I will check the pressure and spark. I had a mechanic put the plugs in but I will double check it. The rest of the stuff I read the codes and put in.

Thank for reply.

Peter

Don't discount the possibility of a defective plug or wire, new or not.