My wife will be driving, and she says the tach will jump and the car surges, but it doesn't do it all the time and when I've driven it I can't get it to do it! And this is on the flat not up hill!

What is your question?

It has never had plugs or wires changed and we've owned it about four years. I just replaced the left exhaust manifold, but it was doing it before. I thought maybe the after the manifold was changed it might stop!