So I have a inconsistent idle. If I let my car warm up to normal operating temp its perfect and smooth at 750 rpms, but usually after driving it will tend to dip to about 500 rpms when coming to a stop, and then adjust up to about a rough feeling 650~700 rpms with a slight miss or "putt" that can be heard from the exhaust and felt on the steering wheel and shift ****. I have replaced my cap and rotor, spark plugs and wires. Cleaned my IACV. Adjusted idle screw.

Today I tested my coil with a multi meter and got the following results: The primary coil tested at .9 to 1 ohm. Out of spec (.6-.8 ohms). The secondary coil tested at 16-18k ohms. Within spec (12.x-19.x). There is lots of oxidation or powdery like substance beneath the dust cap on the distributor. The two screws holding the positive and negative wires for the coil are rusted. Does the out of spec reading on the primary coil suggest that its on the way out or faulty? Can a funky coil cause rough idle and missing?
Thanks

 

rust isn't a good conducter, which i could see raising the resistance on an electrical connection. maybe you should clean off the rust and test it again.

 

The reading before I cleaned the rust off was .9ohms and the reading after was 1ohm! So My resistance seems to have been increased ... I just ordered a new coil, but any other suggestions would be helpful in the mean time!

 

tell the coil to stop resisting and to be more submissive. hope this helps! lol

 

Does anybody have some useful advice?

 

take the distributor apart and check for broken wires going to the ignitor. check distributor shaft for play; bet is wobbling all over the place

 

That shaft does have a little bit of play to it but its a very small ammount. The wires going to the ignitor seem to be in-tact.

 

Today when I was driving home from work the idle was even worse. It seemed to be stuttering when accelerating in 2nd gear at about 2700 to 3000 rpms. I'm really thinking its the coil. What elese could it be considering I have all new cap and rotor, spark plugs and wires, clean IACV, properly adjusted idle screw checked for vacuum leaks... The only things that I need to do is replace the fuel filter, get my timing belt and water pump changed, get my new radiator installed (old one's top seal leaks badly) and get a valve adjustment. Seriously what else could it possibly be????