I put about 600 miles on over the holiday and started to notice a surge when driving. i had the cruise set on 65 and the rpms would surge 1-200 while going down the interstate. it stopped for awhile and then started doing it again. Later in the trip I took the od off and it would still do it. The only thing I have noticed in the past was that it wanted to jump/hunt gears at 45-50 if i was easy on it. If I hammer on it the truck shifts. Any ideas?

Thanks

 

Are you sure it is'nt the converter locking and unlocking?
If you want an easy check, just clean the battery cables. A bad ground can cause electrical noise to get into the computer and do this.

 

I am not sure. I was wondering if it was. It happens at different speeds too. and it usually lasts for a second or maybe two. I will try cleaning the cables.

 

Did you check your fuel psi, my rpms would surge when my first LP was going out.

 

I do not have anything to check the fuel psi with. I was going to buy a tester or some gauges, but I needed to save the money for the wandering front end.

 

I basically had the same problems and found my TPS bad... hope this helps

 

Basically what i am hearing is that it could be many different things and I am just going to have to take it somewhere. Anyone know of a good shop in south-eastern South Dakota?

 

I had the same issues and just wrapped my battery cables / grounds in that foil duct tape, wrapped it all back up and good to go. $10 fix. From what I read, it is electromagnetic interference from the cables crossing over into the APPS thingie, causing mixed signal for lock/unlock of the TC. Every power cable that is hot, produces and EM field. This field is proportional to the current and wire size. It's part of motor/generator action. Now, if you put another wire (or wires in the APPS/TPS thing) near that field, the field can interact with them causing intermittent faults.

Isolating the wire from its environment, via alum duct tape from HD/Lowes, minimizes the field, thus reducing interference.

So, I tried the cheapest route first, and it worked. Next step would have been the choke coil mentioned below.

(Also dismounted the spare grounds from beside the batteries and scraped up the metal some more).

There is also a $50 choke coil to ground setup you can get. I've seen 2 different models on 2 different websites.

Radio shack also has one for like $4, but it doesn't ground, just chokes.

 

I called a transmission guy in Sioux Falls and he said that everytime he has seen this happen it was the tps. So I called a dealer for the part and on the 99 it is not the tps its a whole assembly that is called something else and costs 600 bucks. Why do things always break when you are trying to sell them?

 

so i decided to try and adjust the apps. It was at .449 and the sticker said that it should be at .604. i adjusted it as much as i could and got it to .589. do you have to do anything after that to make it relearn or something like that?

 

Did you check the voltage all the way thru the throttle range? I bet you have a dead spot on it...mine did..

 

I didn't check the entire range. After I disconnected the batteries and did the slow pedal down/up I drove 80 miles with no issues. Hope this fixes it for awhile at least.

 

To recamilbrate the APPS after unplugging or replacing.

Turn the key "ON" do not start.

Press throttle fuly to the floor and return. Shut off key and start truck.

At least that's how I remember the manual reading.

Dave