Speedometer and cruise control issues?

[dds78910]

Today is my Friday at work so I decided to drive my Spirit R/T to work today instead of taking the work bus. It is about 55 miles and this is the first time I have had it on the interstate for more than a couple mile. I have been wanting to get it on the road and kind of test it out to see if it would be dependable for trips and things like that.

Now here is the problem, the car drives really nice, but I'm driving about 80 mph and the speedometer starts to to jump +/- 5-10 mph backand forth for a little while. With the cruise control off it still drives fine, but with the cruise on the car wants to speed up and slow down by itself since the cruise is on. It just seems to happen out of no where and then stopped after a few miles.

Any Ideas? I am tring to make this car a good daily driver and something I can take on 300-400 mile road trips and not have to really worry about anything.

[JDAWG]

Did you check codes? Could be speed sensor or maybe a vaccum problem at the reservoir

[dds78910]

I was going to work and have not had a chance yet. The guy I bought it from removed the air box and then put half of it back on and I noticed some of the vacuum lines didnt look right.

[Tony Hanna]

The vacuum lines for the cruise do look really wierd. When I was redoing mine, my first reaction was "WTF kind of cobbled up mess is this!!??". I thought it was something the previous owner rigged together, but it turned out to be stock. That's assuming you're talking about the triangle of lines that run a boost leak back to the air box.

For your speedo problem, the first thing I'd try is pulling the connector for the speed sensor and cleaning both ends. It might be as simple as a bad connection there.

[dds78910]

It probably is a bad connection, cause it doesnt do it all the time. I probably drove 30 miles before is happend. Then it just stopped.

[LowSL2]

For your speedo problem, the first thing I'd try is pulling the connector for the speed sensor and cleaning both ends. It might be as simple as a bad connection there.

That's what I had to do to mine when I had the same problem. Just a connection issue.

[D1A8J]

would a bad fuse cause this ?!?!?!?!
i know i had alot of fuse issues with my r/t !!!

[supercrackerbox]

Definately sounds like a speed sensor issue to me, my Daytona used to do that all the time until I found a bad spot in the wires and repaired it. Check for a code 15.