I want to apologize in advance for this being so long. I want to be thorough so that maybe someone can help me. I've had it posted for a few days on the other forum and haven't got much response, so hoping since this place is a bit more technical, I may get some more opinions.
Here is the issue, it feels like the truck is slipping into neutral quickly and then back in gear. Or possibly defueling. Or maybe shutting off and starting up right away. But it is rather violent. It does it mostly on the highway after it has been driven for a long distance, but it has also done it around town at low speed after I had been cruising around for an hour or so and it was well warmed up. It has only done it once when it was cold, and it was under a heavy acceleration situation where I pulled out in front of traffic first thing in the morning. That was scary. It is very sporadic, so I can't get a read on what it could be.
Let me give some back story to make sure it is clear and you guys can hopefully pinpoint what I have going on. I tried taking a video, but that turned out terrible. I'm too shaky. I did log a few things on EFI for a couple minutes while it was happening, but I have no clue how to post that.
I bought the truck about 2.5 months ago. It is a high mileage truck ~230k. It appeared to be a really good deal, but I've ended up dumping a good bit of money into it, so I probably would have been better off spending more up front. Oh well. Hindsight. Here is what I've done to it in the last 2 months.
Shocks, UCAs, tie rods, pump rub kit, transgo jr, install gauges, AFE hot side intercooler pipe, full fluid and filter change all the way around, and EFI Live from Kory
The problem was there before I did any of the work, but MUCH less frequent. I'll give some timelines.
When I bought the truck, I drove it home from Denver to Albuquerque - about 6 hours. The odd "drop" happened when I was about 5 hours into the trip, and it happened twice, one right after the other.
Drive it locally around every day and nothing.
Drive from Albuquerque to Roswell - about 3 hours each way. Doesn't do it at all on the way down. Does it 3 times on the way back.
Drive it around locally every day no issues.
Drive from Albuquerque to Phoenix - About 7 hours each way. Doesn't do it at all on the way out. Does it a half dozen times on the way back.
Installed everything except tunes, transgo, gauges, and pump rub kit
Drive it locally every day and it doesn't do it.
Install transgo jr, pump rub kit, tunes and gauges.
Drive it around locally and it doesn't do it.
Drive it from Albuquerque to Baton Rouge - about 18 hours over two days. Does it frequent. Gets worse the longer I drive. Once I stop for the night, the next day, it takes about an hour on the road for it to start again, but it is bucking sporadically, sometimes every 100 yards, sometimes every 5 miles.
Drive it around Baton Rouge and get stuck in traffic. It starts surging and doing it at idle. I try popping it into neutral and it stops, but then starts again after a few seconds.
Drive from Baton Rouge to New Orleans - about an hour. Decided to take the computer with and log it to see if it might be a fuel issue. To be honest, I'm not sure I know what to look for, but assuming I got it right, it COULD be indicative of a FPR, but I can't say for sure, that is just a possibility I read about on here. Commanded pressure is normally the same as Fuel Rail pressure. A few times on the trip back, the Fuel Pressure is reading 1000-2000psi higher than commanded. But only a couple times. It surges the whole way back to Baton Rouge.
Drive from Baton Rouge back to Albuquerque, didn't do it for the first 250 miles, then started it up, and continued the whole way home. One time, while idling in park, it choked out a couple times like it wanted to die, but didn't.
My biggest complaint is that there are no codes being thrown. Nothing at all. No indication of what system is the problem.
Things I noticed that may or may not be of signifigance -
When I was installing the transgo, I realized that the transmission had recently been serviced, and poorly so. They installed the new internal filter without pulling out the old seal. So it was double sealed in the body. Luckily it was tight, so hopefully that didn't do any damage. Unfortunately, them servicing it is probably indicitive of the fact that they knew of this issue and couldn't figure out what it was and chose not to disclose it to me knowing how it only appeared after it was on a long drive.
Doing the pump rub kit, someone had been in the transfer case recently as well. The very obvious poorly done orange RTV was a giveaway. Also, it appears that the tail housing on the allison has been resealed with RTV, done much more professionally. The driveline has had greasable u-joints put on, so all that together I'm curious if a bad u-joint at one point cracked the intermediate case (I think that is what it is called).
On the driver's side, the lower motor mount bolt is missing. I bought one and tried like hell to get it in, but couldn't. But I don't know what jobs, other than motor removal, require removing the mounts.
I'm concerned it could be the transmission taking a crap. Or maybe the CP3/FPR. But there are no codes at all. I drive it easy, but I have no clue about it's past owners.
What do you guys think?
Here is the issue, it feels like the truck is slipping into neutral quickly and then back in gear. Or possibly defueling. Or maybe shutting off and starting up right away. But it is rather violent. It does it mostly on the highway after it has been driven for a long distance, but it has also done it around town at low speed after I had been cruising around for an hour or so and it was well warmed up. It has only done it once when it was cold, and it was under a heavy acceleration situation where I pulled out in front of traffic first thing in the morning. That was scary. It is very sporadic, so I can't get a read on what it could be.
Let me give some back story to make sure it is clear and you guys can hopefully pinpoint what I have going on. I tried taking a video, but that turned out terrible. I'm too shaky. I did log a few things on EFI for a couple minutes while it was happening, but I have no clue how to post that.
I bought the truck about 2.5 months ago. It is a high mileage truck ~230k. It appeared to be a really good deal, but I've ended up dumping a good bit of money into it, so I probably would have been better off spending more up front. Oh well. Hindsight. Here is what I've done to it in the last 2 months.
Shocks, UCAs, tie rods, pump rub kit, transgo jr, install gauges, AFE hot side intercooler pipe, full fluid and filter change all the way around, and EFI Live from Kory
The problem was there before I did any of the work, but MUCH less frequent. I'll give some timelines.
When I bought the truck, I drove it home from Denver to Albuquerque - about 6 hours. The odd "drop" happened when I was about 5 hours into the trip, and it happened twice, one right after the other.
Drive it locally around every day and nothing.
Drive from Albuquerque to Roswell - about 3 hours each way. Doesn't do it at all on the way down. Does it 3 times on the way back.
Drive it around locally every day no issues.
Drive from Albuquerque to Phoenix - About 7 hours each way. Doesn't do it at all on the way out. Does it a half dozen times on the way back.
Installed everything except tunes, transgo, gauges, and pump rub kit
Drive it locally every day and it doesn't do it.
Install transgo jr, pump rub kit, tunes and gauges.
Drive it around locally and it doesn't do it.
Drive it from Albuquerque to Baton Rouge - about 18 hours over two days. Does it frequent. Gets worse the longer I drive. Once I stop for the night, the next day, it takes about an hour on the road for it to start again, but it is bucking sporadically, sometimes every 100 yards, sometimes every 5 miles.
Drive it around Baton Rouge and get stuck in traffic. It starts surging and doing it at idle. I try popping it into neutral and it stops, but then starts again after a few seconds.
Drive from Baton Rouge to New Orleans - about an hour. Decided to take the computer with and log it to see if it might be a fuel issue. To be honest, I'm not sure I know what to look for, but assuming I got it right, it COULD be indicative of a FPR, but I can't say for sure, that is just a possibility I read about on here. Commanded pressure is normally the same as Fuel Rail pressure. A few times on the trip back, the Fuel Pressure is reading 1000-2000psi higher than commanded. But only a couple times. It surges the whole way back to Baton Rouge.
Drive from Baton Rouge back to Albuquerque, didn't do it for the first 250 miles, then started it up, and continued the whole way home. One time, while idling in park, it choked out a couple times like it wanted to die, but didn't.
My biggest complaint is that there are no codes being thrown. Nothing at all. No indication of what system is the problem.
Things I noticed that may or may not be of signifigance -
When I was installing the transgo, I realized that the transmission had recently been serviced, and poorly so. They installed the new internal filter without pulling out the old seal. So it was double sealed in the body. Luckily it was tight, so hopefully that didn't do any damage. Unfortunately, them servicing it is probably indicitive of the fact that they knew of this issue and couldn't figure out what it was and chose not to disclose it to me knowing how it only appeared after it was on a long drive.
Doing the pump rub kit, someone had been in the transfer case recently as well. The very obvious poorly done orange RTV was a giveaway. Also, it appears that the tail housing on the allison has been resealed with RTV, done much more professionally. The driveline has had greasable u-joints put on, so all that together I'm curious if a bad u-joint at one point cracked the intermediate case (I think that is what it is called).
On the driver's side, the lower motor mount bolt is missing. I bought one and tried like hell to get it in, but couldn't. But I don't know what jobs, other than motor removal, require removing the mounts.
I'm concerned it could be the transmission taking a crap. Or maybe the CP3/FPR. But there are no codes at all. I drive it easy, but I have no clue about it's past owners.
What do you guys think?
