As I have said, I have just purchased an FB. Under idle, the car sounds inconsistent when compared to the FD. I hear thrud thrud..thrud thrud...(engine sound) and sometimes sounds if its going to shut down--stumbles quickly and goes back to the normal thrud thrud..thrud thrud. The tachometer still doesn't work after changing the plugs as told. Kind of hard to observe what's going on when it doesn't work. What may be the problems causing the tach not to work? What are the ways it can be fixed? Is the engine sound normal and different from 13Bs? Thanks in advance, this car is worrying me more than my FD.

-RX187

 

The tach works off the trailing ignition, so you sould check the ignitor and coil to make sure that they work. It seems to me that idle quality would be noticely degraded with only the leading ignition fireing. If the trailing ignition is working, you may have a vaccuum leak that is messing up the idle.

 

Agreed. Would put money on the ignitor/coil. Swap the coils and see what happens, if its still the same then swap ignitors. You should have isolated it by then. If yout tach isnt working then its a pretty good indicator of a failed trailing system, the car will run on the leading system with much the symptoms your refering to.

 

Sounds like you got on target. I'll check today. This is probably the problem because my car seems like its misfiring under idle. The fumes are extremely strong too. Thanks guys.

 

I haven't had the time to check yet. I drove it and sometimes it works and sometimes not. It drops to zero at a stop and at times it will work and not. So I'm guessing a vaccuum line now?