The engine cuts out severely above 4500 RPMs and backfires. Every other couple of times it's very hard to start the car and almost wants to run down the battery. The plugs are fine and it idles great at 900 RPMs . It runs very well up to the point of the cutting out and backfiring. This is a relatively new development. It had a valve job at 110,000 miles and it now has 145,000 miles. It's been impeccably serviced. Thanks for any advice I can relay to my mechanic. He's in the process of pulling the valve cover and checking things out in there.
