91 lumina

i got at 91 lumina with a 3.1 in it & i got a problem with the exaust smelling bad & when you be running down the road you can be going 65 & lose speed, & when ya step on the gas it cuts out & i changed the following items, fuel pump, tps, coil pack, ecm, plugs & wires. im wondering if the timing or egr has anything to do with symptoms? any ideas?

You may have a plugged catalytic converter.

Buy a vacuum gauge ($25), hook it to manifold vacuum, and look for 17-21" vacuum at idle, raise RPM's to about 2000 and hold, if reading slowly drops as throttle is held steady, exhaust restriction is indicated.(bad cat) Reading will drop abruptly, then recover when the throttle is first opened, that is normal.

i changed catalytic converter forgot to list it any ideas?

try testing/replacing the fuel pressure regulator.