My car was running poorly during fast acceleration and at speeds over 60 mph. I had the O2 sensor replaced and the MAFS cleaned and recalibrated. The car ran perfect for about 3 months. It started stumbling again. I replaced the MAFS with a remanufactured one from the parts store. Service codes were reading P0031 and P0037. While sitting in park and flooring it, at exactly 4000 rpm the engine cuts out and falls back to 3700 rpm, then races back up to 4000 to cut out again, and cycles like this till I let up off of the gas. The car runs okay while at 30-40 mph as long as I don't try to take off quickly. But if I floor it, forget it. It stumbles badly until I let off the gas. Same at highway speeds over 60. To go over 60 I have to floor it and hold it there. Any ideas? No other codes reported from my CP9580. Thanks!
Wednesday, February 15th, 2012 AT 10:44 PM