Hi, I Have a 91 honda accord lx and just recently while I am driving the speedometer drops
Or goes all over the place. Sometimes when the speedometer is not working for a few miles the check engine light comes on. Also when the speedometer starts working when I am driving I feel a
Power increase. Tripmeter and odo are effected with the changes as well. Please help

1. Check for a blown fuse (likely 15 A) in the under-dash fuse/relay box. Use a test light or multimeter, so you don't replace the fuse in the wrong slot.
2. Check for codes being thrown.
3. Check the variable speed sensor (VSS). It's located on top of the transaxle, close to the firewall. Clean and check the connector. There are various VSS Input Tests (harness side of 3-P connector) that can be performed with a multimeter; also, there are extensive physical and electrical tests that can be performed on the VSS.
4. Check the VSS ground at G101, which should be a 3-wire ground located around the thermostat housing. Remove and clean.


Hopefully, it will be a fuse; otherwise, it can get involved.