I'll tell you what my truck is doing and see if any of you guys can help me out. Every once in a while when I fire the truck up (only time this happens is when cold) the speedo will jump all over the place and the throttle will not work. Sometimes the coolant low light will come on. If you shut it off and start it back up it will be fine, sometimes it takes two times. Then every once in awhile, when you take off down the road and it won't shift past second, but the same thing if you pull over and re-fire it, it will be fine. I thought it might be a ground, so I took apart every one I could find and cleaned them. Is there any grounds that might be hidden that I didn't see? The next thing that I was going to do is replace the ECM.

Thanks

There's a braided ground cable near the starter that ties the block, firewall, and frame together.

You're on the right track.

I found the same problem with my 94 when it came to not shifting into second. Actually it started in second and didn't shift period, making you think its in first.

Anyways the problem for me was simple. New battery's and clean posts, the truck would start just barely and run fairly fine but wouldn't shift until a refire after a short charging time. Hope this helps, did wonders for my 94. Get some juice in those battery's.

The truck does have two new Delco batteries. I will check that other ground.

Thanks for the replies

A couple other things for you to check out...

Pull codes from the computer. To learn how to do this, go to http://kennedydiesel.com/ , click on "Tech Tips", click on "6.2/6.5L Tips", and click on the "Read Codes" picture. Pull codes, disconnect batteries for 1/2hr (resets the codes), reconnect batteries, go for a ride, and pull codes again. Post 'before' and 'after' codes here.

Also, battery cables are known to corrode inside the insulation. Also, the crush washer in the passenger side positive battery connection sometimes wears out and causes issues. Cheap to replace.

huisman has a valid point, no matter how good the battery's are those connections are junk, especially yours if they're still factory side post connections. My 00 was giving me the click click click when trying to start, i thought the starter was going out untill i removed the connections and cut them apart.... uhhhhh! It was amazing i even had power anywhere. I switched to top mount brass now... now i have a new starter in my garage just waiting.... been about 3 months now, no problems to -35C.

My truck's speedo has bounced durring cold starts since I've owned it, always works though, so I never paid it much attention. I have not had any shifting problems so I would say that the bouncing speedo and tranny shifting issues are independent of each other. I do agree with what others have said on this thread about the tranny problem being related to an electrical problem. Look for grounds me and many of my friends have experienced electrical problems with this generation truck, Gas or Diesel, the electrical system leaves much to be desired.

My dad has a 93 suburban and when his alternator was going bad, his gauges did the same thing. They would spike and drop. Just a suggestion, but check and see if the alt. in bad or is going bad.

I'll tell you what my truck is doing and see if any of you guys can help me out. Every once in a while when I fire the truck up (only time this happens is when cold) the speedo will jump all over the place and the throttle will not work. Sometimes the coolant low light will come on. If you shut it off and start it back up it will be fine, sometimes it takes two times. The next thing that I was going to do is replace the ECM.

Thanks
What year and type truck? F or S
I've seen an erratic fast idle with unresponsive APP when my fuel solenoid was wearing out.

I've also noticed the same speedometer erratic behavior on mine and several customers trucks I've worked on, seems to be just part of the nature of the design, I had a ground issue that would kill the speedo and trip the Water In Fuel light too.

I've also seen PMDs cause similair behavior to what your describing, but definitely need to verify the whole electrical system first, if thats not right, nothing will be on an electronic truck. Consistent power and grounds are needed to operate sensors and the PCM.

I have followed the forum for a while now and as a person who is not a tecnician and not familiar with electricity I have learned so much here. The consatnt talk about grounds etc. is great. GM recently replaced my IP under warranty. The truck ran like a bear for two days the began to start hard and was seeing wierd things in the gagues etc. I started checking grounds thanks to this forum and found two that were not tightened well when the pump was replaced. I fixed the two grounds and guess what, truck starts and runs great. Thanks to all you guys with the knowledge you share.

Dan

I have followed the forum for a while now and as a person who is not a tecnician and not familiar with electricity I have learned so much here. The consatnt talk about grounds etc. is great. GM recently replaced my IP under warranty. The truck ran like a bear for two days the began to start hard and was seeing wierd things in the gagues etc. I started checking grounds thanks to this forum and found two that were not tightened well when the pump was replaced. I fixed the two grounds and guess what, truck starts and runs great. Thanks to all you guys with the knowledge you share.

DanYes DMitch, I too have learned alot of do's and don'ts while reading here. This site is full of very knowledge and experence members who love sharing with us less knowledge. And that's what this site is best at and should be all about. Please free feel to join in, as I have seen you do, and help answer others questions when possible.
:Nothing_f

The truck is 94 with 8th VIN "F". I will check codes this afternoon.Thaks

It had a code 16, so I cleared it and drove it and it didn't have any codes. It also never acted up.


Thanks