Question about vibration and information to help others

Hello you all, I have a write up on some things I have done along with the symptoms I was experiencing and how I corrected those issues Hopefully it will help others searching on this forum, as I did! I also have a new issue "Vibration at 1500 RPM in drive only " that I am trying to get figured out, and what I have done to try to fix the vibration as well, so if anyone has any ideas please let me know. Okay here we go!

2014 Crewmax 4x4 5.7 FF
184k
6" lift with FOX coils and BDS subframe "no spacers"
37x12.5 on 20x9 rims


Chapter 1

Hard start, alcohol level, fuel injectors

January I was experiencing a hard start and fuel smell in the exhaust after turning it over a few times to get it to fire in the mornings "below freezing temps". Reading this forum I saw many post users about the fuel alcohol level possibly being high. I had purchased a Launch Creed elite bi-directional reader and checked the level. Shockingly it was at 0, so then I was leaning towards having a leaking fuel injector. Since I have the privilege of being friends with the original owner. I had contacted him and asked if he ever had the fuel injectors replaced. He had said that they are the original injectors. Since my truck is my means of transportation to get to work and back, I opted to buy some re-man denso Injectors from Diecherkz fuel systems in Oklahoma. After installing the re-mans the hard start DID go away.

Chapter 2

After fuel injector install problem.

After installing the re-man denso's, I had a bad vibration coming from the engine, as well as very low performance. Luckily I had new CELs on! It was the p306 and p308 code and the truck went into LIMP mode. I had hooked up the Launch creed reader and looked at the engine misfire data. I did indeed have a misfire on 6 and 8. Since the injectors were new I decided to look into the coil packs. I switched the 6 and 4 coilpack around, reset the ecu then drove the truck long enough to get the CELs on again, which only took 5 minutes of driving. Hooked up the reader and I still had a 6 and 8 misfire. I checked the plugs, but did not see anything of an issue as I had replaced those 9 months ago with densos. I decided to take out the 6 and 8 fuel injector and put 2 of the old ones that I had tested good, back in. WALA! That fixed the issue. I am now working on warranty issues with Diechwerkz on the 2 bad injectors. The truck drives great, and I had always got 11.5 average MPG, and now I am at 14.6 MPG average. Along with the new Injectors, I did replace the PVC valve AND took the throttle body off and cleaned it good.

Chapter 3

Vibration at 1500 - 1600 rpm in drive only

While driving the truck I noticed that I was feeling a vibration at around 1500 rpm while driving down the road. If I let OFF the gas or gave it MORE gas, the vibration would go away. I decided to drive it at 1500 rpm and while on a flat road, I would put it in neutral and the vibration would go away, until I put it back in drive. Also, if the truck is parked I would rev it up too 1500 rpm and DID NOT experience any vibrations. So the truck only vibrates going down the road while the pedal is at at an even acceleration at 1500 rpm. I went to the most likely culprit being driveline or suspension! I thought that since the truck went into LIMP mode that it had caused the weaker problems to finally break in the driveline, because as some of you may know, LIMP mode shakes your truck rapidly and is not forgiving. I went underneath and checked the carrier bearing. The carrier bearing was definitely bad and there was not a carrier bearing drop kit either. I went ahead and purchased 3 spicer U Joints, Spicer carrier bearing and also a 6" carrier bearing drop kit from Coachbuilder. Once installed at the mechanics. I drove it home and the vibration is still there! I took it to discount tire and had the wheels balanced and rotated as well and that didn't do anything either. I went ahead and checked for a possible misfire again with the Launch Creed and absolutely NO misfire! I am almost certain that since the vibration is only while driving, that it has to be suspension or drivetrain related. If you guys have any ideas, let me know. I will come back and document anything else that I do as well as let you guys know what fixes the vibration so that others can learn from this.

Thank you!

 

Damn straight! Haha, sorry for some reason it had posted before I could finish writing it all out.

 

This is interesting not a Tundra but a Tacoma, here: https://youtu.be/vcMHJOG_MHg?si=xGCERxP0ivEgpHOB

 

That was a good video, I remember that channel. In fact I watched one of his episodes on how to read engine data for the fuel trims when I was having the hard start problems. I would love to have the vibration sensors that he has. I have often wondered if it could be a driveshaft issue. I am going to jack it up today and see if I can feel anything loose or out of place. If I can't then more than likely I'll take it to my mechanic, and update this post.

 

Okay guys, I can finally put everything to rest with the issues that I was having with the vibration at 1500 RPM! I had replaced the carrier bearing and all the universal joints with OEM components. That fixed half of the vibration but not all of it. The problem ended up being an issue with the fuel injectors that I had bought. I had contacted Deatschwerks fuel systems about the issue possibly being the fuel injectors. They had no problem with checking them after I had sent them back, I had 2 that had build up inside, which is due because of my fuel rail and contaimanants inside that had gotten into the fuel injector. At the same time they had also told me that the injectors I had bought were high flow injectors that had a higher output of fuel at 650CCs and that I would need a tune. This explained the negative fuel trims I was getting. The customer service and expertise of that company is amazing, they had replaced all injectors with 8 newly renamed Densos. But my decision is to sell them and had my old Densos remanufactured as I did not want to hassle with a tune. I'm sure the truck would be fast, but it just drives me to work and back so factory is just fine! Once I had the factory Densos remanned and flow tested, the truck ran amazing and the vibration at 1500 RPM went away! I hope this can help anyone in the future with looking at it from different angles.