The speedo on my 98 1.8 i six speed mx5 sometimes

Find the speedo cable at transmission and see if it is loose.

Have it scanned.

Your problems sound like they are electrical, i would suggest you take it to an electrician and have them identify the problem, it most likely is not the speedometer as all that does is just output the speed, the speed sensor might be one thing you can look at.

The abs speed sensor is on the rear diff. as you read. Your truck may have 2-whl antilock or 4-whl antilock brakes. The sensor on the rear costs about $40. Sometimes it can be easy to replc. if not too stuck, but take care not to crack it or drop pieces into the rear end. inspect the wires for loose or broken connections. Now if the code is for wheel speed sensors on the front hubs, then it will be over $100 each.

Hi,

The speedo dial on your cluster is controlled by the Vehicle Speed Sensor.

This sensor is mounted on top of the transmission case.

This condition is either caused by a loose connection (wirig loom) or a faulty sensor (see item # 7 on diagram below).


7. Vehicle speed sensor connector

Change the Engine speed sensor. This can sometime cause your dash to do all sorts of weird things when they fail, such as setting the low fuel warning off as well. strange but true ! good luck

have the fault codes read
the speedo gets its signal from the VSS ( vehicle speed sensor) and that sensor also reports to the transmission control module
So check for a problem in that area

does vehicle have vss or a vehichle speed sensor or is it a cable drive speedo

Speedometer or fuel gage?

If speedometer which is bouncing around, it is likely a bad ground near where the speed sensor wire harness (which connects the speed sensor to the rest of the "network") exits the transmission housing. It's at the very back of the transmission (you have a 4T60E trans) to the left of where the right side half-shaft leaves the trans housing. Just look for damaged wires. If none, replace the speed sensor for $50-60.

If it is the fuel gage, the sensor is probably not "zeroed"--it's reading wrong, too high, and if it were to start at true "empty", it would read right. Thus, the gage is always reading a little high (maybe a 1/8-1/10th of a tank too high?). This isn't a problem until to stop, start, or turn quickly and cause the fule to slosh around in the tank and starve the in-tank pickup which sends fuel to the engine.

If it is the fuel gage, you should simply put as much fuel in as you can and see if the needle goes far above "F". If it does, note how far it went and then practice filling the tank when the needle is that same distance above "E".

Hope this helps.

This happen to me too. Had to get it replaced under my exstended warrenty that cost me the $200 deductable but would of coast over $400 if this happened later.