human Posted August 12, 2009 Report Share Posted August 12, 2009 My dad gave me his '97 Concours yesterday and as we were driving around to the bank, DMV, etc. to get the paperwork done, I noticed the engine felt like it was missing when we were stopped at traffic lights with the car in gear and my foot on the brake. The tachometer would momentarily drop from 1,000 to 900 rpms whenever a "miss" would occur. Once the light would turn green and we started moving, things would smooth out and the car would run just fine. As I drove home (about a 100-mile trip), the car ran fine but the cruise control quit working about halfway there. When I got off the interstate and stopped at the first traffic light, the engine was idling rougher than ever, but would smooth out as soon as I put it in either Park or Neutral. Dad said a mechanic friend of his (retired from Hendrick Motorsports) had replaced one of the ignition coils last fall when the car began to run rough, not just when stopped at traffic lights, but all the time. Could another coil be on the way out? Could the rough idle and the cruise control failure be symptoms of something worse like the computer failing? I had a '94 Olds 88 a few years ago that had a computer failure. The first symptom was loss of cruise control. A few months later, the car started running rough and stalling in traffic. After replacing the computer, it ran smooth as silk and the cruise control worked again. Any insights would be greatly appreciated. The secret to flying is to throw yourself at the ground--and miss! --Douglas Adams Life, The Universe, and Everything Link to comment Share on other sites More sharing options...
fredv Posted September 4, 2009 Report Share Posted September 4, 2009 I had the same problem when i bought my car. It is the same year and model. I took it to the stealership and did the 100,000 mile service. with new plugs and wires. It turns out that the number eight piston wasnt firing so it had rough idle. The idle was also a little rough off of starts but then it ran smooth. I havent has a problem with it since... till the heater core. Good Luck Fred Link to comment Share on other sites More sharing options...
human Posted September 23, 2009 Author Report Share Posted September 23, 2009 It got progressively worse over the past six weeks and I put a new set of ignition coils (the three that weren't replaced last year) in it yesterday and now it runs like a dream. The cruise control failure is documented when I pull up trouble codes, but it hasn't returned My dad gave me his '97 Concours yesterday and as we were driving around to the bank, DMV, etc. to get the paperwork done, I noticed the engine felt like it was missing when we were stopped at traffic lights with the car in gear and my foot on the brake. The tachometer would momentarily drop from 1,000 to 900 rpms whenever a "miss" would occur. Once the light would turn green and we started moving, things would smooth out and the car would run just fine. As I drove home (about a 100-mile trip), the car ran fine but the cruise control quit working about halfway there. When I got off the interstate and stopped at the first traffic light, the engine was idling rougher than ever, but would smooth out as soon as I put it in either Park or Neutral. Dad said a mechanic friend of his (retired from Hendrick Motorsports) had replaced one of the ignition coils last fall when the car began to run rough, not just when stopped at traffic lights, but all the time. Could another coil be on the way out? Could the rough idle and the cruise control failure be symptoms of something worse like the computer failing? I had a '94 Olds 88 a few years ago that had a computer failure. The first symptom was loss of cruise control. A few months later, the car started running rough and stalling in traffic. After replacing the computer, it ran smooth as silk and the cruise control worked again. Any insights would be greatly appreciated. The secret to flying is to throw yourself at the ground--and miss! --Douglas Adams Life, The Universe, and Everything Link to comment Share on other sites More sharing options...
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