Lots of info on the forums for your reading pleasure concerning the items mentioned.

Unless your speedo is jumping all over the place, I wouldn't worry about your VSS.

Does the vibration/misfire/whatever it is occur if you place the shifter in 3rd gear? Does it only occur at around the same throttle position or is it speed dependent more than anything else?

I'm not sure what you are calling the "transmission coil"...

From the sounds of it, you are no longer thinking it is a 4wd problem...

 

Definitely it has a 4x4 problem, but its the actuators, TCM and Vacuum under the battery, but im not worried for these, ill get them fixed later, im worried of the crappy performance of the truck.

-Speedo its jumping all over the place but only when I make a quick turn at 30mph or higher speed, rpm jumps up and down for a while, then both needles just go down slowly and a moment later it resumes normal operation.

-Misfire its mainly on idle, on the road you cant feel it, sometimes I gets a little stronger but just for like 5 seconds.

-Vibration its only when passing 50mph and 60mph it’s the max speed no matter what I do, even if I floor gas, and its slooooow increasing the speed.

-Transmission coil like I mentioned in the previous post was a solenoid of the tranny.

Yup, this truck its gonna keep me busy for a while.

 

I must have missed the jumping speedo symptom... Could be wiring or the VSS itself. I would try to get the simple things like this knocked off first. Check over the wiring and remove/clean the sensor and see what happens. The resistance and mV-AC output that you should expect from the VSS through testing has been posted before. A search of "VSS+resistance" should return the pertinent results.

Which solenoid did you replace in the transmission? There are a few. When you accelerate, is the transmission hitting every gear (1-4)?

 

Found the VSS+Resistance post so im gonna check it tonight.

About the solenoid its the one at the side of the transmission filter, i dont know if it is the A,B, etc, i didnt have a camera to take pictures, sorry.

Truck shifts ok from 1,2,3 even before replacing the solenoid, but when i pass 40 mph it builds speed slower, when 50mph the shift feels like... well lazy, i mean you have to floor the gas and vibration starts, if i don let go the pedal starts vibrating stronger if i loose it for one second and then resume accel vibration stops, +50mph speeding gets even more slower, its difficult to mantain the speed and vibrations goes on and on, at 60mph its the speed limit and vibration shows more often, feels like driving a boat, strange tough that the speedo only gets crazy on turns at more than 30mph and not when the vibration and lazyness shows its ugly face.

Im driving her only to 40mph until y ran some diagnostics.

Thanks for your reply!.

 

I did some work to the truck this weekend, haven’t check the VSS, i was pretty much entertained on the throttle body cleaning, air filter hoses where fine, one of the three resistors on MAF was totally black, the butterfly was really a problem, its my first time cleaning this type of intake that is facing up, it was full of carbon everywhere, and i notice that it was getting stuck, EGR was full of carbon too, i cleaned everything!.

Now the truck accelerates like a champ!, but i still have the problem of the vibration, i have done some test and i realized that tranny is shifting correctly in 1,2,3 and OD, but its like something its messing with the tranny performance, im sure now that the vibration comes from the center of the truck, maybe one of the mounts, im gonna take the truck to a tranny shop to see if they find out the problem.

Overall im driving the truck without problems, just some minor complaints...

-Everything inside rattles!!!, cheap plastic, im gonna see the possibility to get some screws with little plastic caps so they do not look so ugly and screw the hell of all the rattling cheap plastic parts.

-Suspension its so hard that i feel even the slightest stone in the road, my dad has a Grand Cherokee and is so smooth on the suspension, i know this kind of trucks are like this but anyone knows how to smooth it a little?.

So im pending with...

-VSS check.
-Vibration when 45 to 60 MPH.
-Bring back to life the 4x4.
-Find and relocate splice pack.
In the meantime im enjoying the ride, its a nice truck... when it works!.

Thank you everyone for your replies, ill keep you informed about TACHICOMA Status (that’s her name).

 

Well i have some news...

-Checked both sensors on the end of transmission (VSS and the other), both are fine.

-Took Tachicoma to tranny shop, done some test..... the vibration its from the tranny...., just when OD its suppose to hit, thats why it was like towing a trailer on the highway, it gets stuck on 3rd but trying to get OD, it does get in OD after some time but the vibration starts, if i shift the tranny into 3rd accelerates faster and the vibration its minimal but still there. Cost...Very high (1200Dlls for rebuilt)... im getting a second opinion and price meanwhile i drive with 3rd on the highway (finally at more than 40mph!!!).

-And i discovered something new!, i have a leak in the rear seal of the transfer case, minimal, but its there!.

Now questions...

-In the morning 9 a.m., truck accelerates faster, has power, in the afternoon 4 p.m. weather its really hot, truck feels without power, lazy, in the night 9 p.m. its slightly better but not to much..... im crazy? .

-Im not using 4x4, do i need to repair the transfer case leak?, or its dangerous?, Could the possible low oil in the transfer case cause my 4x4 always 2lo problems?, tranny shop said that until i do not use the 4x4 doesnt matter if the transfer case has oil..... im confused....

-There is any way to make the trip in this truck more comfortable?, mean i feel the sand when i drive!!!!! kind of struts, coils, mumbo jumbo?....

-I saw that from one side there is like 3 steel bars (i dont know the name in english, in spanish are called "muelles") in the left rear suspension but in the right there is only 2, im missing one or this is normal?.

-Any recommendation on the tranny?, im thinking about get one 2wd from the yard but i dont know if its going to work or like i saw on other threads "have to change the front diferential or even the whole chasis"

Can anyone help me to solve these questions?, im in a countdown, baby its on the way and my wife its getting tired of me spending so much time and money on this truck, i was looking for some V6, comfortable, medium space truck, high enough to survive the floods to come the rest of the year.... i miss my 1994 K5, but i dont want to give up on this truck yet, i like the body and the style, even withouth 4x4, well im trying my best.

 

You should fix the transfer case leak. Sooner or later it could leave you stranded if not repaired.

Cooler air will make more power than hot air. Depending on how much of a difference you are experiencing, this could be perfectly normal. There are also other factors that could impact performance such as humidity having an impact on the ignition system if there are some weak areas in the plug wires or distributor cap that the moisture is allowing spark to leak out of.

There should be the same number of leaves in the leaf springs on both sides.

Concerning the transmission, I would fix what you have.

One last thing... Your posts are very difficult to read due to the small font you have chosen. If your post is difficult to read, people may not bother reading it and move on to another post. To help you get the best responses from the most people, please do not alter the text formatting.

 

Thanks for your reply swartlkk.

Sorry about the font, didnt know about what you say, thought i was making them interesting and funny, im only Verdana now.

Well i guess i have a long way of repairs to go with this truck, sadly i cant do much right now so last repairs are going to be....

-Take her to suspension shop to see what can be done about the leaf springs, if they are going to remove one to the left or add one to the right.

-Fix transfer case leak.

-Balance, alignment and rotation of tires.

Well thats it, tranny would have to wait, im not spending 1200 dlls, its not worth it for me right now (i hope it to last for a while), depending on how the truck responds ill keep it or sell it.

Thank you everyone, even the ones that didnt reply to my thread, because this forum its very handy, there is a lot of valuable information here, its amazing really, have spent hours reading all sections, nice people, great trucks.

Huston out.

 

Well im back, i still have the truck, 4x4 works now, one of the problems was the lockup pin of the front actuator, garbage really, i just build one with a O keychain that fits perfectly and its stronger than the previous crap, i cleaned all the connectors and TCCM with dielectric and everything works, 4hi, 4lo, 2hi, and the auto 4wd, 2 weeks without problems so far, no more random 4x4 engaging or neutral.

I have spend 0$ dlls apart from Gasoline since my last reply, im not fixing anything until i know for sure what the problem is, so a friend of mine has some Elm357 usb scanner and we run some tests this weekend, there is a lot of information and im having trouble to identify any problems, im uploading the results file in excel to see if someone can help me to diagnose any of it.

Main issues are:

1.- Vibration from tranny when going up to 40mph, i think its the TC but im not changing it until its properly diagnose because i have read that several other issues can cause this condition, tranny swaps for nothing but ending with the same issue, etc.

2.- Very slow acceleration, its frustrating.

3.- 11 MPG fuel economy, sucks.

Have other issues less important:

1.- Transfer case leak on the rear output shaft seal, cant find the seal anywhere, im waiting to a tranny shop that order it from the dealer.

2.- Leaf springs, left side there is 4 of them, right side only 3, doesnt seem to be a problem but i want to fix it to, truck doesnt look more higher from one side or another tough.

It does something strange too, before i start the truck, in the ON position, the conector of the injectors commonly known as spider, fuel octopus or whatever, starts to make some clicking noise that never stops but i dont have problems starting the truck, no SES codes.

Just to mention it, the buddy that have the Elm357 scanner did some reset to the PCM, i was not sure about this but when i drove the truck it was working like a charm, lots of power, high response, but the vibration at 40mph was still present a couple of days and it was back to laziness, weird.

Im not fixing anything until the main issues are resolved, its hard to maintain a vehicle with so many problems and worst yet that knowing what is the problem its a real PITA, so any help will be appreciated.

Huston out.

 

Here's a few things you can try that will only cost a bit in gas. First for the clicking noise, pull the connector off the spider and check for corrosion. Also with it off turn the key on and see if it still clicks, the IAC could be clicking as its trying to open all the way due to a "low idle". Leave the key on for a few mins, five or ten should be long enough, connect the spider connector back and try starting the truck, she should fire right up, if it takes longer to start then you could have a fuel leak and pressure is bleeding down. Also try revving the engine up slowly and see if it vibrates with just the engine spinning. The 4300 Vortec uses a Balance shaft in the engine, and if its off for some reason then it would cause a vibration. Also jack up all four wheels making sure there is at least two inches from the tread to the ground, and put it in gear and spin the wheels to 60 mph. Have a buddy look at the drive lines and see if they do anything weird. Try this in 2 hi and 4 hi making sure you stop the wheels before putting it in 4 hi. If you decide to swap your trans with a used one, you can use a 2 wheel drive, but you have to swap out the tail piece from the two so you can connect it to your transfer case. I believe you said you have the ZR2 suspension package, which means you've got the 31 inch tires, which means more weight to move, and lower mileage. To improve the ride quality, you could try air shocks, or smart shocks with velocity sensing valves to ease up the ride. That should help some.