I know my speedometer is very of at 30 mph im going 25 mph and it gets worse off the faster I go once I went 95 mph and someone on the highway passed me I know it could be another crazy driver like me but it was a family vehicle with children so I dont think His speed was that excessive any Ideas to fix it It bothers me not knowing for sure how fast Im going

 

I would suggest a couple of things. (I just went through this myself. Mine was over 4 tenths of a mile slow per mile) I can't quite understand from your post if you think it is fast or slow, so the first thing will apply only of your speedo is slow, the second item you can use regardless of if it is fast or slow.

1. Check your speedo cable and be sure it is in good shape. You can pull the guts out of the sleeve the slip it back in real easy. If it is starting to frey or rust, replace it. If it is dry, lube it up real good with a lithium type grease. My cable was bone dry, and just lubing it stopped the needle bounce and reduced the error to around 2.5 tenths of a mile/mile slow.

2. Having done that, if it is still off, you can replace the speedo gear in the tranny, which is a 2 minute job on a C-6 (undo the screw holding the cable to the tranny and pull on the cable)



Find a set of odometer calibration markers on the freeway, if your state puts those out. We have them all over the place here in NW Washington. If you don't have those, then just use the mile markers on the freeway (and hope they are in the right spot.) I would recommend going several miles and taking an average. Go through the mile markers and figure out how many tenths of a mile your odometer is off. For every 2 tenths of a mile, you will need to add or subtract 1 tooth. If your odometer is slow, you will need to SUBTRACT a tooth. So, pull the gear, count the teeth, add or subtract what you need and call your good 'ole Ford dealership. I paid $8.69 for my gear.

You may hit a situation like I did where your odometer is not exactly .2 or .4 off, it is something like .23 or .3 off. If that is the case you will not be able to get it EXACT, but you will be able to get it a lot closer.

I learned this technique from the parts guy at my local Ford dealership, and is much easier than all the formulas floating around on the net. And seems to work. I have not gone to the calibration markers to recheck it, but when I am reading 45 in a 45 zone, I am not blowing everybody else's doors off like I would have in the past.

I hope this helps.

 

it is slow when my speedometer reads 30 im really going 25 but did your speedometer get even hurther off the faster you go

 

The error is always a % of the speed. At an indicated 60 mph you would be going 50, etc.

That speedo calibration method sounds great! -Nice and simple