Toyota pickup tach bounces and sometimes drops out

what I have encountered in the past is the ABS module was the cause. what happens is the wire connections become loose and fail to make proper contact, causing the brake,abs, and speedo to stop for short or long periods of time.if equiped with a tach it also will jump from 0 to 1500 or other places. I have noticed that the other components such as speed sensor,abs plugs, or instrument panels does not make all of the above things do this all at once. like I said this has been my findings and only suggesting a hopeful fix for your issue. best of luck to all.

You just go to the link I attached I'm sure you will get the solution of your problem
1998 Dodge Caravan Service Repair Factory Manual INSTANT DOWNLOAD

Change the cable(speedometer cable)it is being damaged by steering assembly.check it out...

does it have ac if so watch your ac compresor if it engages and your rpm drops at the same time thats the issue

Sounds to me like your transmission is just plain worn out from running with no fluid in it. I have an early 5 speed from the 1988 Toyota that works fine if your interested. I have the same from an "84 in my "86 Toyota pickup I just took off the road last January. The '94/'95 should be the same if you want to keep your truck on the road. Mine had frame rot, typical of these trucks.

OK THE SETTING IS 5 DEG BEFORE TOP DEAD CENTER BUT YOU HAVE TO JUMP OVER TE1 AND E-1 IN FUSE BOX IN ENGINE COMPARTMENT THIS GROUNDS IGN SYSTEM. TAKE BACK OFF AFTER AJUSTMENTS COMPLETED

if your o2 sensor is reading too lean then you have a vacume leak spray brake cleaner on all your vacume hoses one at a time if nothing then spray it around your intake manifold gasket they are usually the culprit

sounds like you may have a problem with your speed o gear in trans.

loosen the distributor slightly so you can turn it. attach timing light and check timing which should be 5 btdc. it would be a good idea to tune up the baby before you time it. also check tach readings. about 750 when warm should be ok

well if your car is running normal and not bucking and stalling and shimming all over then i would think about changing the tachometer perhaps good place to start.John