Have 78 280Z. Had bad coil wire and changed it and car started great. Changed plug wire #1, car started great. From #2 onwards could not get a start. Put back old plug wirs and will start, but rough idle and noticable exhaust. Checked seating of all wires and look good. Thoughts?

Stating the obvious here- verify cap/wire/plug firing order. Connection/seating won't help if the firing order is off.

Thanks for the reply....Yup, did them one at a time vs the old wires. Now starts with full new set, but still getting a rougher idle than usual and more visible exhaust out the pipe.

Maybe during the wire change, the cap/rotor became dislodged. It happens.

There are wires and connectors in the distributor area that can be disturbed, such as coolant sensor, thermo-time, etc.

The point is- if everything was fine, excepting the coil wire, and then you changed something (the wire set) and now there is a new problem, you have to troubleshoot the problem from scratch, as if you have a no-start engine. Fuel,fire,air. Clean connections. Good grounds. Properly installed and adjusted components. Can't get a wrinkle out carpet without pushing it to the edge 'til it's gone...

sweaty/salty hands? If you left enough salt and moisture behind, you might have a short to ground.

I agree with loosened temp sensor connection : rich exhaust, rough running and in the area

Thanks everybody....once I had the full set on again I moved on to other items (air filter, interior stuff) and let the car sit for a bit. Started right up a bit later, took it out for a ride and seemed ok, parked and started again later.

Blue...thanks for the pics...will check these tomorrow; too hot in the garage right now (4pm facing west in Florida is brutal).

If the temp sensor loosens then the car will run very rich. It may even carbon foul the plugs.

If you find it loose then attach and check your plugs.