"Nervous" Tachometer

Hi everyone,

Recently my tachometer was really jittery. When I was accelerating,
upon reaching about 3,000 RPMs the tach needle started jumping back and
forth rapidly between 3k & 5k RPM even though I was only accelerating
gradually. I noticed it seemed like my car was "missing" periodically too.
I found out my distributor cap was only being held on by one screw (I didn't
know this initially) and was in fairly bad shape. (Contacts worn and
rusted, rotor button also in bad shape) Well, I replaced the cap and rotor
button, (cap held on by 3 screws now, as it's supposed to be) as well as the
spark plugs. The spark plugs I took out looked OK, but I figured going to
Bosch Platinum wouldn't hurt. ;-) That almost cleared it up. It still
gets a little jittery around 5,500RPM (6,500 redline) but nowhere near as
bad as before. If I get new plug wires, could that possibly clear up the
high-RPM jitters? Should I clean (or possibly replace) the distributor?
What else could be causing this? Any ideas?

Thanx in advance!

Jonathan

P.S. Car type: 1990 Honda Civic LX 5-speed 1.5L DPFI - all stock engine
parts

 

I had a similar problem on my Toyota. Turned out to be the magnetic pick-up
coil in the distributor.

Carl

 

I bet the ignitor is going. bob

 

Ignitor was my first guess as well - it's a known weak point in some Hondas
of that vintage. A couple of years ago, I had similar symptoms in my '90
CRX Si that persisted even after I'd replaced the cap/rotor/plug wires,
and it turned out to be a bad ignitor.

Dave