Where would I start?? When my speed o says I am doing 90MPG...my GPS says I am doing 65MPH...it is very linear...meaning at when it say 45MPH it I am doing 30MPH....always 15MPH high???? Is this something to do with the cluster, or something possibly to do with the gear where the cable goes into the tranny???

I am having issues with the temp gauge for the cluster...I suspect it is a bad ground... but just have not had time to pull it apart... Thx

Oh..it is a '88 civic 1.5L LX model

 

a) 90 mpg and 65 mph are two different things
b) if you meant 90 mph then that's a 25 mph difference
c) do you have huge riced out wheels that are larger than stock?

 

when you arent moving what does the speedometer read? 15mph?

 

assuming you dont have 20 inch wheels on the car, it sounds like you have a poor cluster ground, or a defective cluster.

also inspect the VSS cable for damage.

 

No I have the stock 13" wheels...I didn't think a bad ground would affect the speedo being it was a mechinal cable....I also have the problem with the temp gauge which I am pretty sure is a ground so that would make sense that I have 2 problems both related to a ground issue....

Sorry, yes I ment 90MPH....not MPG

 

If your speedo reads higher than your moving, you wheel diameter would be "smaller" not "larger" than stock. Big ricer wheels would make it read slower.

 

I was told that 13" rims were what stock is??? Was I told wrong??

either way, is there any way of changing something to will get me back to normal? I was thinking the gear in the tranny???

 

stock wheels are 195/45/14 14" not 13 thus the 14 in the tire.

 

My stock wheel's where 13's. The 1" difference is not even close to being enough to account for the 15mph that your speedo is out by.

 

same thing happend to me...my rpms were messed up as well..vtec popped at 3 grand lol....i just replaced my cluster and everything went back to normal again