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Do-overs are nice indeed. :( Sorry to hear about the problems. I think most of us have been there before at some point if that makes you feel any better.

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Finally some good news.  Seattle injection found a piece in the governor armature broken and 5K springs installed.  They said this definitely could have caused the missing problem.  Otherwise the pump checked out good.  They are going to correct the issues and the pump might be back on the truck as early as Friday.  Hope she turns out good as new.  Based on how the prior owner built this thing, I hope I got here soon enough before there was any damage done to the engine.  

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That's great!!!!!! Its nice to find the smoking gun! There is nothing worse than never finding the Gremlin's 

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Well, back to square one.  The pump work all of the other work and the truck still has a miss/vibration.  When I first felt this I thought I might have been a bad ujoint.  That's what the feeling is.  Plateau called it a fishbite miss.  At any rate, its still there.  Plateau is stumped.  However, one of the first things I asked for they never did....  a compression test.  Early on they said they didn't think it needed it.  Sooooo…  come Monday it should be done.  After those results we will continue to try and figure it out.  The only part of the engine not looked at other than compression is the cam.  At this point the torque converter has come up in conversation as well.  If anyone has an idea on this, we are looking for things to chase.

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It’s tough chasing little things as a new owner where you have no clue when or how it started for guidance. 

I wonder if you had it on a dyno holding where the problem was most defined if it would help to check where it’s coming from could look for vibration also check motor for any temp variance between cylinders might give insight to the cause. 

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I didn't go back and read.

 

Have they already checked your lift pump pressures?  At Idle at higher RPM?

 

I've heard stories where lift pump caused some issues?

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11 hours ago, C Paul Go said:

I didn't go back and read.

 

Have they already checked your lift pump pressures?  At Idle at higher RPM?

 

I've heard stories where lift pump caused some issues?

They put a new lift pump on and verified pressure to the injector pump.  Kind of in a weird place.  Picked the truck up today, but really don't know where to look next.  I am going to look particularly at the harmonic balancer, motor mounts, transmission mounts, etc.  Next will be to run this by the transmission shop and talk about possible transmission contributing factors.  It will vibrate at 1300rpm in neutral.  However, running about 40 in underdrive, it will go through the RPM range pretty smoothly.  Shift into overdrive and all hell breaks loose from about 1300 to 1600rpm.  I can play with the vibration.  shift into overdrive and it will vibrate pretty good if you are in the rpm range.  Get a little harder in the throttle and it will vibrate a bit harder, back out of the throttle it will smooth out.  Snap out of the throttle and it will vibrate harder again on decal.   Stomp it and it stays above the problem rpm and is pretty smooth through the shifts and up on to freeway speed.  65 to 70 on freeway at 1900 give or take and the truck runs out smooth.  Beats the heck out of me.,

 

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They put a new lift pump on and verified pressure to the injector pump.  Kind of in a weird place.  Picked the truck up today, but really don't know where to look next.  I am going to look particularly at the harmonic balancer, motor mounts, transmission mounts, etc.  Next will be to run this by the transmission shop and talk about possible transmission contributing factors.  It will vibrate at 1300rpm in neutral.  However, running about 40 in underdrive, it will go through the RPM range pretty smoothly.  Shift into overdrive and all hell breaks loose from about 1300 to 1600rpm.  I can play with the vibration.  shift into overdrive and it will vibrate pretty good if you are in the rpm range.  Get a little harder in the throttle and it will vibrate a bit harder, back out of the throttle it will smooth out.  Snap out of the throttle and it will vibrate harder again on decal.   Stomp it and it stays above the problem rpm and is pretty smooth through the shifts and up on to freeway speed.  65 to 70 on freeway at 1900 give or take and the truck runs out smooth.  Beats the heck out of me.,
 
Hopefully this ends up being a simple fix! You've come so far!

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Didn’t re-read thread

 

drive shaft been checked for balance ?

IIRC u-joints were addressed 

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So, here is the latest update on this.  Starting at ground zero, I went back to the driveshaft.  After playing with it for awhile I managed to get some movement on one of the sides of the ujoint at the rear axle.  I pulled the driveshaft and the bearing caps that go into the rear end yoke were shiny like the bearing caps were spinning.  I took the driveshaft to drivelines NW.  They replaced the ujoints and straightened a slight 20 thousands bend in the driveshaft at the rear weld.  I replaced the rear yoke with one that uses ubolts rather than the straps.  I have only driven it a couple of miles, but it feels better.  Not completely better, but considerably better.  I need to get more seat time to really tell.  Next stop....  Fluidampr.

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So, here is the latest update on this.  Starting at ground zero, I went back to the driveshaft.  After playing with it for awhile I managed to get some movement on one of the sides of the ujoint at the rear axle.  I pulled the driveshaft and the bearing caps that go into the rear end yoke were shiny like the bearing caps were spinning.  I took the driveshaft to drivelines NW.  They replaced the ujoints and straightened a slight 20 thousands bend in the driveshaft at the rear weld.  I replaced the rear yoke with one that uses ubolts rather than the straps.  I have only driven it a couple of miles, but it feels better.  Not completely better, but considerably better.  I need to get more seat time to really tell.  Next stop....  Fluidampr.
Well that's great progress!

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I had my front and rear driveshafts done by Drive lines NW before I realized something in my clutch is causing random vibrations. I don't regret it though. At 150+k miles it didn't hurt to do them and they did great work. 

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20 hours ago, SMOKN05 said:

I had my front and rear driveshafts done by Drive lines NW before I realized something in my clutch is causing random vibrations. I don't regret it though. At 150+k miles it didn't hurt to do them and they did great work. 

 

At the end of the day, I am a bit suspect of the torque converter.  It is nice that the driveline work gave me some relief but I can still feel the issue.  So I am starting a longer horizon look for a replacement transmission.

 

One thing that I find really interesting is that when I bought the truck, you could mash the pedal and nothing happened  until high RPM.  At that stage the tranny shifted like it is supposed to with no detectable slipping.  Truck went like a bat out of hell.  With all of the work that I have had done, the torque is fat down low where I want it to be, and if I am not careful I can slip the trans.  

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At the end of the day, I am a bit suspect of the torque converter.  It is nice that the driveline work gave me some relief but I can still feel the issue.  So I am starting a longer horizon look for a replacement transmission.
 
One thing that I find really interesting is that when I bought the truck, you could mash the pedal and nothing happened  until high RPM.  At that stage the tranny shifted like it is supposed to with no detectable slipping.  Truck went like a bat out of hell.  With all of the work that I have had done, the torque is fat down low where I want it to be, and if I am not careful I can slip the trans.  
I can say for sure that is exactly how my 12 valve acted when I had it. I had according to hard parts roughly 300 to 350. It was a very factory trans aswell.

I've read but have not tried, that you can upgrade the Tc and either do shift kit or valve body to work under about 400 hp.

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O.k.  I have been trying to get acquainted with my 98 12V automatic and I am running across a couple issues that may or may not be related.  First, when I start this thing up, it looks like I am getting blue smoke.  I know if I let it idle for a long time and take off, it looks to be burning oil off of the pistons  (old Detroit terms).  That part goes away when fully warmed up.  Blowby is on the high side for my likes pretty much all of the time.  I need to do an oil change.  It was pretty clean when I picked it up from the dealer, but it could be 3 years old based on the history I got with the truck.  So, then this thing runs what I would call rich.  Seems smoky at idle pretty much most of the time.  Plus, this thing builds EGT's like right now.  In regular stop light to slow traffic, it will get to 800 EGT pretty darn quick and with very little pedal.  Climbing a hill, the truck will make the big shift to overdrive and the EGT will go to 1100/1200 within a few seconds if I don't back out of the throttle and downshift.  I am trying to figure out the setup on this.   Its running a BD Super B turbo, but the turbo really seams like its set for higher RPM.  I can hit 40lbs of boost laying into it on the highway.  But this thing doesn't seem to like low RPM much.  When it shifts into overdrive kind of lazily pulling a hill, it wants to quit pulling, belch black smoke and run EGT's through the roof.  Hit the hill like a bat out of hell and everything sings and sets you back in your seat.  Quite frankly I hate that.  I like to loaf and hang on the torque powering on up the hill.  I know this is a mish mash of stuff but any thoughts on this as far as where to look first would be appreciated.  I have not pulled the fuel plate to see what it is running as of today.  Thanks for your thoughts.  
A separate question. Do you have 3 piece manifold or a factory exhaust manifold? I had some egt problems with my 12 valve then I put a 3 piece manifold on and my truck wouldnt go above 1000 degrees before I had to slow down.

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9 hours ago, srt6 said:

A separate question. Do you have 3 piece manifold or a factory exhaust manifold? I had some egt problems with my 12 valve then I put a 3 piece manifold on and my truck wouldnt go above 1000 degrees before I had to slow down.

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I have the 3 piece manifold.  EGT's are reasonable at this point.

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