So far I have had a very good experience with the members on here helping me out. So my issue now with my 1990 Vanden Plas Majestic (23,631 miles) is not so much a rough idle but a consistent inconsistent feeling to the spark....hope that makes sense. I guess the feeling is similar to a car having a cam in it, but at a more rapid pace. It stays steady at 800 RPM's on the tachometer, but you can feel that rapid lopey type feeling in the seat and if the door is open, you can see it shaking up and down. I cleaned off the rotor and put another distributor cap on it and it hasn't changed anything. Hopefully someone can point me in the right direction because these cars seem to have so many nuances, I want to start here with those who have experience with them.

 

Do you mean there is a miss? 800 is a bit high, should be 650-700. Maybe check the intake system, they tend to need "mucked out" every so often because of the suction from the engine. Dont worry too much. Not a huge problem.

 

Yes it feels like a slight miss. I will check the intake system tomorrow. As for the RPMS I believe I am not giving it enough time to fully warm up because I do not want to run it long the way it is right now. When I get this miss situation figured out, I will definitely check to see if it settles around 650-700. Thanks for your input

 

Ok I checked the intake system from air filter to Throttle body. Nothing out of the ordinary and actually quite clean. Little bit of carbon build up on the ends of the flaps but definitely not enough to cause any kind of intake issues. I replaced the rotor yesterday so now cap and rotor are new. I pulled all the plugs and cleaned them off. They appeared as if the engine was running rich. I put everything back and got the same ole miss.