Sirs:

Chevrolet 454 cid with electronic ignition, 1991. When engine is cold runs perfectly. After engine warms up it has a serious "miss" at 65 MPH. Slowing down or speeding up will cause the engine to level out and the miss seems to disappear. I replaced the oxygen sensor a few weeks ago per a set code. There are no other set codes in the readout.

Any suggestions?

Thanx

 

When's the last time it saw a tuneup? Start with my "The Basics" post.